Annual report pursuant to Section 13 and 15(d)

Other Non-Current Assets (Narrative) (Details)

v3.10.0.1
Other Non-Current Assets (Narrative) (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Nov. 01, 2016
Nov. 30, 2018
Sep. 30, 2017
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Mar. 31, 2018
Other Assets, Noncurrent [Line Items]                  
Ownership interest (as a percent)   27.00%             43.00%
Upfront consideration           $ 0 $ 445 $ 0  
Investment in private companies   $ 1,200              
Class B units                  
Other Assets, Noncurrent [Line Items]                  
Units owned (in shares)           538,776      
Historical purchase price           $ 1,250      
Class A units                  
Other Assets, Noncurrent [Line Items]                  
Number of shares purchased (in shares) 1,500,000   1,450,000            
Ownership interest (as a percent) 21.40%   34.50%            
Upfront consideration $ 1,500   $ 1,450            
Company's share of loss           $ 1,146 $ 1,469    
Maximum | Class A units                  
Other Assets, Noncurrent [Line Items]                  
Ownership interest (as a percent)           50.00%      
Scenario, Forecast                  
Other Assets, Noncurrent [Line Items]                  
Mandatory capital contribution payments       $ 1,100 $ 1,200