Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity Stock Incentive Plan and Net Income per Share - Employee Stock Purchase Plan (Details)

v3.20.4
Shareholders' Equity Stock Incentive Plan and Net Income per Share - Employee Stock Purchase Plan (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Schedule of Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]      
Share-based compensation $ 11,033 $ 11,715 $ 10,191
Employee Stock Purchase Plan [Member]      
Schedule of Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]      
Number of shares authorized under the plan 335,000    
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date 90.00%    
Purchase Period for Employee Stock Purchase Plan 6 months    
Number Of Large Lump Sum Contributions Related To ESPP Stock Purchases 2    
Employee Stock Purchase Plan [Member] | Continuing Operations      
Schedule of Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]      
Common stock issued under employee stock purchase plan (in shares) 14,000 11,000 8,000
Weighted average price of shares purchased (dollars per share) $ 44.24 $ 51.50 $ 50.62
Weighted Average Grant Date Fair Value $ 20.99 $ 13.68 $ 6.26
Share-based compensation $ 292 $ 150 $ 54
Employee Stock Purchase Plan [Member] | Discontinued Operations      
Schedule of Employee Stock Purchase Plan (ESPP) Disclosures [Line Items]      
Common stock issued under employee stock purchase plan (in shares) 1 1 1
Weighted average price of shares purchased (dollars per share) $ 44.35 $ 51.39 $ 50.64
Weighted Average Grant Date Fair Value $ 18.11 $ 13.48 $ 6.27
Share-based compensation $ 20 $ 13 $ 5