Quarterly report pursuant to Section 13 or 15(d)

Recent Accounting Pronouncements (Details)

v3.10.0.1
Recent Accounting Pronouncements (Details)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
$ / shares
Sep. 30, 2017
USD ($)
$ / shares
Sep. 30, 2018
USD ($)
$ / shares
Sep. 30, 2017
USD ($)
$ / shares
Dec. 31, 2017
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Accounts Receivable, Net, Current $ 148,464   $ 148,464   $ 147,948
Number of principal reporting segments     4    
Operating revenue 331,375 $ 298,289 $ 964,325 $ 844,209  
Operating Income (Loss) 29,879 27,176 86,984 80,914  
Income Tax Expense (Benefit) 7,077 8,557 21,289 27,522  
Net income $ 22,329 $ 18,328 $ 64,366 $ 52,575  
Diluted (in dollars per share) | $ / shares $ 0.76 $ 0.61 $ 2.18 $ 1.73  
Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   $ 298,289   $ 844,209  
Operating Expenses   271,113   763,295  
Operating Income (Loss)   27,176   80,914  
Income Tax Expense (Benefit)   8,557   27,522  
Net income   $ 18,328   $ 52,575  
Diluted (in dollars per share) | $ / shares   $ 0.61   $ 1.73  
Expedited LTL [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue $ 186,544 $ 164,702 $ 546,066 $ 472,723  
Operating Income (Loss) 23,724 23,189 71,023 65,164  
Expedited LTL [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   165,399   474,636  
Truckload Premium Services [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   51,461   148,999  
Pool Distribution [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue 47,177 40,125 132,980 116,542  
Operating Income (Loss) 735 681 3,695 3,672  
Pool Distribution [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   40,183   116,741  
Intermodal [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue 50,496 44,077 148,058 110,191  
Operating Income (Loss) 7,321 3,785 16,333 9,548  
Intermodal [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   44,161   110,307  
Elimination [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating Income (Loss) $ (3,574) (603) $ (7,415) (1,204)  
Elimination [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   (2,915)   (6,474)  
Scenario, Previously Reported [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   280,201   794,700  
Operating Expenses   253,303   714,804  
Operating Income (Loss)   26,898   79,896  
Income Tax Expense (Benefit)   8,453   27,131  
Net income   $ 18,155   $ 51,948  
Diluted (in dollars per share) | $ / shares   $ 0.60   $ 1.71  
Scenario, Previously Reported [Member] | Expedited LTL [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   $ 155,703   $ 448,571  
Scenario, Previously Reported [Member] | Truckload Premium Services [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   45,941   132,912  
Scenario, Previously Reported [Member] | Pool Distribution [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   39,180   113,838  
Scenario, Previously Reported [Member] | Intermodal [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   42,292   105,853  
Scenario, Previously Reported [Member] | Elimination [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   (2,915)   (6,474)  
Restatement Adjustment [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   18,088   49,509  
Operating Expenses   17,810   48,491  
Operating Income (Loss)   278   1,018  
Income Tax Expense (Benefit)   104   391  
Net income   $ 173   $ 627  
Diluted (in dollars per share) | $ / shares   $ 0.01   $ 0.02  
Restatement Adjustment [Member] | Expedited LTL [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   $ 9,696   $ 26,065  
Restatement Adjustment [Member] | Truckload Premium Services [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   5,520   16,087  
Restatement Adjustment [Member] | Pool Distribution [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   1,003   2,903  
Restatement Adjustment [Member] | Intermodal [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   1,869   4,454  
Restatement Adjustment [Member] | Elimination [Member] | Adjustments for New Accounting Pronouncement [Member]          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Operating revenue   $ 0   $ 0