CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Class A Common	Class B Common	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 loss	(24,200)								(24,200)
Net income	(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)
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]
Net income	342
Ending balance (in shares) at Jun. 30, 2020				90,709,951	79,270,861	(14,620,175)
Ending balance at Jun. 30, 2020	671,536			$ 1	$ 0	$ (199,817)	646,455	278,653	(53,756)
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)
Beginning balance (in shares) at Mar. 31, 2020				90,875,472	79,270,861	(14,620,175)
Beginning balance at Mar. 31, 2020	666,741			$ 1	$ 0	$ (199,817)	640,861	276,628	(50,932)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	7,757						7,757
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)				(40,849)
Shares withheld for employee taxes upon conversion of restricted stock (in shares)				(124,672)
Shares withheld for employee taxes upon conversion of restricted stock	(2,163)						(2,163)
Other comprehensive loss	(2,824)								(2,824)
Net income	2,025							2,025
Ending balance (in shares) at Jun. 30, 2020				90,709,951	79,270,861	(14,620,175)
Ending balance at Jun. 30, 2020	671,536			$ 1	$ 0	$ (199,817)	646,455	278,653	(53,756)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to retained earnings for adoption of ASC 326	671,536			1	0	(199,817)	646,455	278,653	(53,756)
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
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 loss	9,443								9,443
Net income	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)
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]
Net income	18,736
Ending balance (in shares) at Jun. 30, 2021				92,666,590	78,081,076	(14,620,175)
Ending balance at Jun. 30, 2021	745,509			$ 1	$ 0	$ (199,817)	662,727	319,626	(37,028)
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)
Beginning balance (in shares) at Mar. 31, 2021				92,242,152	78,331,591	(14,620,175)
Beginning balance at Mar. 31, 2021	729,721			$ 1	$ 0	$ (199,817)	657,852	310,046	(38,361)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	8,176						8,176
Conversion Class B to Class A common stock (in shares)		250,515	(250,515)
Issuance of shares related to restricted stock units and awards, net of forfeitures (in shares)				281,030
Shares withheld for employee taxes upon conversion of restricted stock (in shares)				(107,107)
Shares withheld for employee taxes upon conversion of restricted stock	(3,301)						(3,301)
Other comprehensive loss	1,333								1,333
Net income	9,580							9,580
Ending balance (in shares) at Jun. 30, 2021				92,666,590	78,081,076	(14,620,175)
Ending balance at Jun. 30, 2021	745,509			$ 1	$ 0	$ (199,817)	662,727	319,626	(37,028)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustment to retained earnings for adoption of ASC 326	$ 745,509			$ 1	$ 0	$ (199,817)	$ 662,727	$ 319,626	$ (37,028)