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Stock-based Compensation - Employee Stock Purchase Plan (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
May 09, 2018
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Aggregate number of shares of common stock issued or transferred under the incentive stock awards plan (in shares)   3,570,891    
Employee Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
ESPP purchase price of common stock, percent of market price, on first and last day of trading date 85.00%      
Fixed contribution rate 10.00%      
Maximum contribution amount $ 25      
Compensation cost for ESPP   $ 600 $ 500 $ 200
Number of shares issued under the ESPP   52,107 46,642 25,239
Weighted average grant date fair value (in dollars per share)   $ 38.55 $ 42.07 $ 35.74
Aggregate number of shares of common stock issued or transferred under the incentive stock awards plan (in shares)   75,314    
Employee Stock | Continuing Operations        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Compensation cost for ESPP   $ 300 $ 200 $ 100