Annual report pursuant to Section 13 and 15(d)

Revenue Recognition - Revenue Recognized (Details)

v3.20.4
Revenue Recognition - Revenue Recognized (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Revenue from Contract with Customer [Abstract]      
Performance obligations satisfied $ 57 $ 4,567  
Changes in the estimated transaction price allocated to performance obligations satisfied in prior periods 774 1,442  
Performance obligations satisfied from new activities in the period - contract revenue 68,225 62,449  
Total revenues $ 69,056 $ 68,458 $ 60,594