CONSOLIDATED STATEMENTS OF EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
BALANCE at Dec. 31, 2012	$ (100,053)	$ 600,928	$ (713,697)	$ (4,993)	$ 16,897		$ 523		$ 289
BALANCE (in shares) at Dec. 31, 2012							52,332,012		28,933,859
Increase (Decrease) in Stockholders' Equity
Dividends declared on Class A and Class B Common Stock	(56,767)		(56,767)
Issuance of common stock, net of issuance costs	472,913	472,733					$ 180
Issuance of common stock, net of issuance costs (in shares)							18,000,000
Class B Common Stock converted into Class A Common Stock							$ 29		$ (29)
Class B Common Stock converted into Class A Common Stock (in shares)							2,905,502		(2,905,502)
Redemption of 3% Convertible Debentures, net of taxes	8,602	8,599					$ 3
Redemption of 3% Convertible Debentures, net of taxes (in shares)							338,632
4.875% Convertible Debentures converted into Class A Common Stock, net of taxes	10,235	10,229					$ 6
Class A Common Stock issued pursuant to employee benefit plans (in shares)							569,423
Class A Common Stock issued pursuant to employee benefit plans	5,100	5,100
Tax benefit on share based awards	521	521
Distributions to noncontrolling interests	(10,256)				(10,256)
Issuance of subsidiary share awards	344				344
Class A Common Stock sold by variable interest entity, net of taxes	7,008	7,008
Other comprehensive income	2,440			2,440
Net income	75,817		73,468		2,349
BALANCE at Dec. 31, 2013	405,704	1,094,918	(696,996)	(2,553)	9,334		$ 741		$ 260
BALANCE (in shares) at Dec. 31, 2013							74,145,569		26,028,357
Increase (Decrease) in Stockholders' Equity
Dividends declared on Class A and Class B Common Stock	(61,103)		(61,103)
Class B Common Stock converted into Class A Common Stock							$ 1		$ (1)
Class B Common Stock converted into Class A Common Stock (in shares)							100,000		(100,000)
Repurchases of Class A Common Stock	(133,157)	(133,109)					$ (48)
Repurchase of Class A Common Stock (in shares)							(4,876,121)
Class A Common Stock issued pursuant to employee benefit plans (in shares)							209,451
Class A Common Stock issued pursuant to employee benefit plans	11,512	11,510					$ 2
Tax benefit on share based awards	1,365	1,365
Distributions to noncontrolling interests	(6,936)				(6,936)
Deconsolidation of variable interest entity	(23,801)	4,518		(546)	(27,773)
Other comprehensive income	(3,356)			(3,356)
Net income	215,115		212,279		2,836
BALANCE at Dec. 31, 2014	405,343	979,202	(545,820)	(6,455)	(22,539)		$ 696		$ 259
BALANCE (in shares) at Dec. 31, 2014						69,578,899	69,578,899	25,928,357	25,928,357
Increase (Decrease) in Stockholders' Equity
Dividends declared on Class A and Class B Common Stock	(62,733)		(62,733)
Repurchases of Class A Common Stock	$ (28,800)	(28,812)					$ (11)
Repurchase of Class A Common Stock (in shares)	(1,100,000)						(1,107,887)
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	11,624					$ 3
Tax benefit on share based awards	712	712
Distributions to noncontrolling interests	(9,918)				(9,918)
Issuance of subsidiary share awards	1,750				1,750
Other comprehensive income	5,621			5,621
Net income	176,099		171,524		4,575
BALANCE at Dec. 31, 2015	$ 499,678	$ 962,726	$ (437,029)	$ (834)	$ (26,132)		$ 688		$ 259
BALANCE (in shares) at Dec. 31, 2015						68,792,483	68,792,483	25,928,357	25,928,357