CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock Class A Common	Common Stock Class B Common	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to retained earnings for adoption of ASC 326	$ 688,159	$ 1	$ 0	$ (199,817)	$ 636,461	$ 278,246	$ (26,732)	$ 65	$ 65
Beginning balance (in shares) at Dec. 31, 2019		90,327,728	79,369,411	(14,620,175)
Beginning balance at Dec. 31, 2019	688,159	$ 1	$ 0	$ (199,817)	636,461	278,246	(26,732)	65	65
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	7,164				7,164
Exercise of stock options (in shares)		23,183
Exercise of stock options	183				183
Conversion Class B to Class A common stock (in shares)		98,550	(98,550)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		574,082
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(148,071)
Shares withheld for employee taxes upon conversion of restricted stock	(2,947)				(2,947)
Other comprehensive income (loss)	(24,200)						(24,200)
Adjustment to retained earnings for adoption of ASC 326	666,741	$ 1	$ 0	$ (199,817)	640,861	276,628	(50,932)	$ 65	$ 65
Net income (loss)	(1,683)					(1,683)
Ending balance (in shares) at Mar. 31, 2020		90,875,472	79,270,861	(14,620,175)
Ending balance at Mar. 31, 2020	666,741	$ 1	$ 0	$ (199,817)	640,861	276,628	(50,932)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to retained earnings for adoption of ASC 326	666,741	1	0	(199,817)	640,861	276,628	(50,932)
Adjustment to retained earnings for adoption of ASC 326	708,714	$ 1	$ 0	$ (199,817)	655,444	300,890	(47,804)
Beginning balance (in shares) at Dec. 31, 2020		91,617,450	78,331,591	(14,620,175)
Beginning balance at Dec. 31, 2020	708,714	$ 1	$ 0	$ (199,817)	655,444	300,890	(47,804)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	5,533				5,533
Exercise of stock options (in shares)		165,311
Exercise of stock options	1,110				1,110
Conversion Class B to Class A common stock (in shares)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)		619,090
Shares withheld for employee taxes upon conversion of restricted stock (in shares)		(159,699)
Shares withheld for employee taxes upon conversion of restricted stock	(4,235)				(4,235)
Other comprehensive income (loss)	9,443						9,443
Adjustment to retained earnings for adoption of ASC 326	708,714	$ 1	$ 0	$ (199,817)	657,852	310,046	(38,361)
Net income (loss)	9,156					9,156
Ending balance (in shares) at Mar. 31, 2021		92,242,152	78,331,591	(14,620,175)
Ending balance at Mar. 31, 2021	729,721	$ 1	$ 0	$ (199,817)	657,852	310,046	(38,361)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to retained earnings for adoption of ASC 326	$ 729,721	$ 1	$ 0	$ (199,817)	$ 657,852	$ 310,046	$ (38,361)