CONSOLIDATED STATEMENTS OF EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Additional Paid-In Capital	(Accumulated Deficit) Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
BALANCE (in shares) at Dec. 31, 2014				69,578,899	25,928,357
BALANCE at Dec. 31, 2014	$ 405,343			$ 696	$ 259	$ 979,202	$ (545,820)	$ (6,455)	$ (22,539)
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(62,733)						(62,733)
Repurchase of Class A Common Stock (in shares)				(1,107,887)
Repurchases of Class A Common Stock	(28,823)			$ (11)		(28,812)
Class A Common Stock issued pursuant to employee benefit plans (in shares)				321,471
Class A Common Stock issued pursuant to employee benefit plans	11,627			$ 3		11,624
Tax benefit on share based awards	712					712
Distributions to noncontrolling interests	(9,918)								(9,918)
Issuance of subsidiary stock awards	1,750								1,750
Other comprehensive income	5,621							5,621
Net income	176,099						171,524		4,575
BALANCE (in shares) at Dec. 31, 2015				68,792,483	25,928,357
BALANCE at Dec. 31, 2015	499,678			$ 688	$ 259	962,726	(437,029)	(834)	(26,132)
Increase (Decrease) in Stockholders' Equity
Cumulative effect of adoption of new accounting standard	2,264					431	1,833
Dividends declared and paid on Class A and Class B Common Stock	(65,909)						(65,909)
Repurchase of Class A Common Stock (in shares)				(4,892,461)
Repurchases of Class A Common Stock	(136,283)			$ (48)		(136,235)
Class A Common Stock issued pursuant to employee benefit plans (in shares)				400,512
Class A Common Stock issued pursuant to employee benefit plans	16,773			$ 4		16,769
Distributions to noncontrolling interests	(10,722)								(10,722)
Issuance of subsidiary stock awards	1,346								1,346
Class B Common Stock converted into Class A Common Stock (in shares)				257,673	(257,673)
Class B Common Stock converted into Class A Common Stock	0			$ 2	$ (2)
Other comprehensive income	27							27
Net income	250,762						245,301		5,461
BALANCE (in shares) at Dec. 31, 2016		64,558,207	25,670,684	64,558,207	25,670,684
BALANCE at Dec. 31, 2016	557,936			$ 646	$ 257	843,691	(255,804)	(807)	(30,047)
Increase (Decrease) in Stockholders' Equity
Dividends declared and paid on Class A and Class B Common Stock	(71,364)						(71,364)
Repurchase of Class A Common Stock (in shares)				(997,300)
Repurchases of Class A Common Stock	(30,287)			$ (10)		(30,277)
Class A Common Stock issued pursuant to employee benefit plans (in shares)				510,238
Class A Common Stock issued pursuant to employee benefit plans	19,126			$ 5		19,121
Distributions to noncontrolling interests	(22,416)								(22,416)
Issuance of common stock, net of issuance costs (in shares)				12,000,000
Issuance of common stock, net of issuance costs	487,883			$ 120		487,763
Other comprehensive income	(616)							(616)
Net income	594,104						576,013		18,091
BALANCE (in shares) at Dec. 31, 2017		76,071,145	25,670,684	76,071,145	25,670,684
BALANCE at Dec. 31, 2017	$ 1,534,366			$ 761	$ 257	$ 1,320,298	$ 248,845	$ (1,423)	$ (34,372)