Stockholders' Equity - Capital Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Nov. 18, 2020	Aug. 15, 2018
Capital Stock
Stock Repurchased During Period, Value	$ 1,321
Common Class B
Capital Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares issued	19,720,381	19,720,381
Common stock, shares outstanding	19,720,381
Common Class A
Capital Stock
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares issued excluding treasury shares	20,468,879
Common stock, shares issued	25,712,338	25,457,709
Number of shares repurchased	127,458
Aggregate purchase price	$ 1,300
Share repurchased	200,000
Total aggregate purchase price	$ 1,700
Remaining authorization for future repurchases	$ 18,300
Common Class A | Maximum
Capital Stock
Authorized repurchase amount				$ 20,000