Operations and Summary of Significant Accounting Policies (Tables)
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12 Months Ended | 
Dec. 31, 2021  | 
| Accounting Policies [Abstract] | 
 
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| Property and Equipment | 
 Property and equipment as of December 31, 2021 and 2020 consisted of the following: 
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December 31, 2021 | 
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December 31, 2020 | 
 
| Land | 
$ | 
26,479  | 
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$ | 
26,365  | 
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| Buildings and improvements | 
67,269  | 
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65,923  | 
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| Equipment | 
259,030  | 
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246,949  | 
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| Leasehold improvements | 
13,780  | 
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13,747  | 
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| Computer software | 
26,333  | 
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23,480  | 
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| Construction in progress | 
27,071  | 
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4,055  | 
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| Total property and equipment | 
419,962  | 
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 | 
380,519  | 
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| Less accumulated depreciation and amortization | 
200,867  | 
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190,652  | 
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| Total property and equipment, net | 
$ | 
219,095  | 
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$ | 
189,867  | 
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| Schedule of Goodwill | 
 Changes in the carrying amount of goodwill during the years ended December 31, 2021, 2020 and 2019 are summarized as follows: 
 
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Expedited Freight | 
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Intermodal | 
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Consolidated  | 
 
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| Balance as of December 31, 2019 | 
$ | 
137,034  | 
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$ | 
78,665  | 
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$ | 
215,699  | 
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| Acquisitions | 
28,234  | 
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1,049  | 
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29,283  | 
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| Balance as of December 31, 2020 | 
$ | 
165,268  | 
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$ | 
79,714  | 
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$ | 
244,982  | 
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| Acquisitions  | 
4,020  | 
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 | 
17,750  | 
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21,770  | 
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| Balance as of December 31, 2021 | 
$ | 
169,288  | 
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$ | 
97,464  | 
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$ | 
266,752  | 
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| Weighted-Average Useful Life of Acquired Intangible Assets | 
The acquired intangible assets have a weighted-average useful life as follows:
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| Intangible Assets | 
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Weighted-Average Useful Life | 
 
| Customer relationships | 
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15 years | 
 
| Non-compete agreements | 
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4 years | 
 
| Trade names | 
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4 years | 
 
 
The estimated useful life of acquired intangible assets as of the acquisition date are summarized in the following table: 
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Estimated Useful Lives | 
 
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FSA | 
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O.S.T. | 
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Linn Star | 
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CLW | 
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Proficient Transport | 
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J&P | 
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BarOle | 
 
| Customer relationships | 
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15 years | 
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10 years | 
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15 years | 
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7 years | 
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8 years | 
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12 years | 
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8 years | 
 
| Non-compete agreements | 
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5 years | 
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3 years | 
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1 year | 
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5 years | 
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1 year | 
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5 years | 
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5 years | 
 
  
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| Finite-lived Intangible Assets Amortization Expense | 
 Changes in the carrying amount of acquired intangible assets during 2021 and 2020 are summarized as follows:  
  
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Gross Carrying Amount | 
 
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Customer Relationships1
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Non-Compete Agreements | 
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Trade Names | 
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Total | 
 
| Balance as of December 31, 2019 | 
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$ | 
196,225  | 
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$ | 
6,652  | 
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$ | 
1,500  | 
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$ | 
204,377  | 
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| Acquisitions | 
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32,191  | 
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 | 
1,473  | 
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—  | 
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33,664  | 
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| Balance as of December 31, 2020 | 
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$ | 
228,416  | 
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$ | 
8,125  | 
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$ | 
1,500  | 
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$ | 
238,041  | 
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| Acquisitions | 
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22,961  | 
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1,051  | 
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—  | 
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24,012  | 
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| Balance as of December 31, 2021 | 
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$ | 
251,377  | 
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$ | 
9,176  | 
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$ | 
1,500  | 
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$ | 
262,053  | 
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Accumulated Amortization | 
 
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Customer Relationships1
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Non-Compete Agreements | 
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Trade Names | 
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Total | 
 
| Balance as of December 31, 2019 | 
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$ | 
73,868  | 
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$ | 
4,152  | 
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$ | 
1,500  | 
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$ | 
79,520  | 
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| Amortization expense | 
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12,062  | 
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 | 
1,427  | 
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—  | 
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13,489  | 
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| Balance as of December 31, 2020 | 
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$ | 
85,930  | 
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$ | 
5,579  | 
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$ | 
1,500  | 
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$ | 
93,009  | 
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| Amortization expense | 
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13,164  | 
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1,164  | 
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—  | 
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14,328  | 
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| Balance as of December 31, 2021 | 
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$ | 
99,094  | 
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$ | 
6,743  | 
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$ | 
1,500  | 
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$ | 
107,337  | 
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1 Carrying value as of December 31, 2021 and 2020 is inclusive of $16,501 of accumulated impairment.
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| Schedule of Accrued Liabilities | 
Accrued expenses as of  December 31, 2021 and 2020 consisted of the following:
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December 31, 2021 | 
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December 31, 2020 | 
 
| Accrued payroll and related items | 
$ | 
29,364  | 
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$ | 
18,545  | 
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| Insurance and claims accruals | 
21,172  | 
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17,994  | 
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| Payables to leased capacity providers | 
11,085  | 
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14,725  | 
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| Accrued expenses | 
$ | 
61,621  | 
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$ | 
51,264  | 
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| Self-Insurance Loss Reserves | 
Below is a summary of the Company’s risk retention on vehicle liability insurance coverage maintained by the Company through $10,000:
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Company  Risk Retention | 
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Frequency | 
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Policy Term | 
 
| Expedited Freight¹ | 
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| LTL business | 
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$ | 
3,000  | 
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Occurrence/Accident² | 
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$0 to $3,000  | 
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10/1/2021 to 10/1/2022 | 
 
| Truckload business | 
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$ | 
2,000  | 
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Occurrence/Accident² | 
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$0 to $2,000  | 
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10/1/2021 to 10/1/2022 | 
 
| LTL business | 
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$ | 
6,000  | 
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Policy Term Aggregate³ | 
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$3,000 to $5,000  | 
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10/1/2021 to 10/1/2022 | 
 
| LTL, Truckload and Intermodal businesses | 
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$ | 
2,500  | 
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Policy Term Aggregate³ | 
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$5,000 to $10,000  | 
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10/1/2021 to 10/1/2022 | 
 
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| Intermodal | 
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$ | 
1,000  | 
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Occurrence/Accident² | 
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$0 to $1,000  | 
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10/1/2021 to 10/1/2022 | 
 
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¹ Excluding the Final Mile business, which is primarily a brokered service.
 
² For each and every accident, the Company is responsible for damages and defense up to these amounts, regardless of the number of claims associated with any accident.
 ³ During the Policy Term, the Company is responsible for damages and defense within the stated Layer up to the stated, aggregate amount of Company Risk Retention before insurance will respond.
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| Net Income (Loss) per Share | 
A reconciliation of net income (loss) attributable to Forward Air and weighted-average common shares outstanding for purposes of calculating basic and diluted net income (loss) per share during the years ended December 31, 2021, 2020 and 2019 is as follows: 
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2021 | 
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2020 | 
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2019 | 
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| Numerator: | 
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| Net income and comprehensive income from continuing operations | 
$ | 
116,091  | 
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$ | 
52,767  | 
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$ | 
82,322  | 
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| Net (loss) income and comprehensive (loss) income from discontinued operation | 
(10,232) | 
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(29,034) | 
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4,777  | 
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| Net income attributable to Forward Air | 
$ | 
105,859  | 
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$ | 
23,733  | 
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$ | 
87,099  | 
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| Income allocated to participating securities from continuing operations | 
(807) | 
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(385) | 
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(945) | 
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| Loss allocated to participating securities from discontinued operation | 
70  | 
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—  | 
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—  | 
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| Income allocated to participating securities | 
(737) | 
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(385) | 
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(945) | 
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| Numerator for basic and diluted net income per share for continuing operations | 
$ | 
115,284  | 
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$ | 
52,382  | 
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$ | 
81,377  | 
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| Numerator for basic and diluted net (loss) income per share for discontinued operation | 
$ | 
(10,162) | 
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$ | 
(29,034) | 
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$ | 
4,777  | 
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| Denominator: | 
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| Denominator for basic net income per share - weighted-average number of common shares outstanding | 
27,155  | 
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27,631  | 
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28,195  | 
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| Dilutive stock options and performance share awards | 
137  | 
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66  | 
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113  | 
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| Denominator for diluted net income per share -  weighted-average number of common shares and common share equivalents outstanding | 
27,292  | 
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27,697  | 
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28,308  | 
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| Basic net income (loss) per share: | 
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|     Continuing operations | 
$ | 
4.25  | 
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$ | 
1.90  | 
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$ | 
2.89  | 
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|     Discontinued operation | 
(0.37) | 
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(1.05) | 
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0.17  | 
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Net income per share1
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$ | 
3.87  | 
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$ | 
0.84  | 
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$ | 
3.06  | 
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| Diluted net income (loss) per share: | 
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|     Continuing operations | 
$ | 
4.22  | 
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$ | 
1.89  | 
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$ | 
2.87  | 
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|     Discontinued operation | 
(0.37) | 
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(1.05) | 
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0.17  | 
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| Net income per share | 
$ | 
3.85  | 
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$ | 
0.84  | 
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$ | 
3.04  | 
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1 Rounding may impact summation of amounts.
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| Schedule of Anti-Dilutive Shares Not Included in Calculation of Net Income per Diluted Share | 
 The number of shares that were not included in the calculation of net income (loss) per diluted share because to do so would have been anti-dilutive for the years ended December 31, 2021, 2020 and 2019 are as follows: 
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2021 | 
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2020 | 
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2019 | 
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| Anti-dilutive stock options | 
—  | 
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206  | 
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183  | 
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| Anti-dilutive performance shares | 
—  | 
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15  | 
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—  | 
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| Anti-dilutive restricted shares and deferred stock units | 
—  | 
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3  | 
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—  | 
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| Total anti-dilutive shares | 
—  | 
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224  | 
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183  | 
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