CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Parent [Member]	Member's Deficiency	Accumulated Deficit	Treasury Stock	Accumulated Other Comprehensive Income	Noncontrolling Interests	Common Class A Common Stock	Common Class B Common Stock
Beginning balance at Dec. 31, 2020	$ (1,203,139)	$ (1,141,030)	$ 0	$ (985,641)	$ (163,866)	$ 3,646	$ (62,109)	$ 2,972	$ 1,859
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to stockholders	274,136	274,136		274,136
Net income attributable to noncontrolling interests	(4,403)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(6,356)	(6,356)				6,356
Foreign currency translation adjustment, net of income taxes	619	619				619
Share-based compensation expense (equity classified)	27,964	27,964		27,964
Redeemable equity vested	20,131	20,131		20,131
Change in redeemable equity	2,528	2,528		2,528
Class A shares acquired through share repurchase program and retired	(522,673)	(522,673)		(522,521)				(152)
Conversion of Class B to Class A shares								1	(1)
Issuance of common shares pursuant to employee long term incentive plan	2,044	2,044		2,037	6			1
Other	58	(4,244)		(4,244)			4,302
Ending balance at Mar. 31, 2021	(1,387,573)	(1,334,169)	0	(1,185,610)	(163,860)	10,621	(53,404)	2,822	1,858
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated deficit	(848,836)
Beginning balance at Dec. 31, 2021	(870,902)	(819,788)	18,005	(848,836)	0	6,497	(51,114)	2,703	1,843
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to stockholders	196,551	196,551		196,551
Net income attributable to noncontrolling interests	(5,590)						(5,590)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(1,843)	(1,843)				1,843
Foreign currency translation adjustment, net of income taxes	(170)	(170)				(170)
Share-based compensation expense (equity classified)	40,512	40,512	40,512	0
Conversion of Class B to Class A shares								0	0
Issuance of common shares pursuant to employee long term incentive plan	10	10	10	0	0			0
Ending balance at Mar. 31, 2022	(626,566)	$ (581,042)	$ 58,527	$ (652,285)	$ 0	$ 8,170	$ (45,524)	$ 2,703	$ 1,843
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated deficit	$ (652,285)