Consolidated Statements of Changes in Equity Statement - USD ($) $ in Thousands	Total	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Class A Common Stock [Member] Common Stock [Member]	Class B Common Stock [Member] Common Stock [Member]	Conversion of Class B Common Stock to Class A Common Stock [Member]	Conversion of Class B Common Stock to Class A Common Stock [Member] Class A Common Stock [Member] Common Stock [Member]	Conversion of Class B Common Stock to Class A Common Stock [Member] Class B Common Stock [Member] Common Stock [Member]	Settlement of the prepaid stock purchase contract component of the TEUs [Member]	Settlement of the prepaid stock purchase contract component of the TEUs [Member] Additional Paid-in Capital [Member]	Settlement of the prepaid stock purchase contract component of the TEUs [Member] Class A Common Stock [Member] Common Stock [Member]
Stockholders' Equity, Balance at Dec. 31, 2012	$ 1,500,462	$ 872,134	$ 789,727	$ 47,271	$ (209,266)	$ 579	$ 17
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME	271,296		271,296
Other comprehensive loss	(41,182)			(41,182)
Dividends paid on Series A-1 Preferred Stock	(2,139)		(2,139)
Value of stock issued for stock-based compensation	12,510	12,504				6
Conversion of Shares to Class A Common Stock								$ 0	$ 1	$ 1	$ 399,389	$ 399,329	$ 60
Compensation cost related to stock-based compensation	16,951	16,951
Excess tax benefits from stock-based compensation	6,854	6,854
Value of treasury stock repurchased	(11,095)				(11,095)
Settlement of deferred stock awards	274	274
Noncontrolling interest, change in fair value	(5,045)	(5,045)
Stockholders' Equity, Other	795	795
Stockholders' Equity, Balance at Dec. 31, 2013	2,149,070	1,303,796	1,058,884	6,089	(220,361)	646	16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME	260,755		260,755
Other comprehensive loss	(78,341)			(78,341)
Value of stock issued for stock-based compensation	11,819	11,815				4
Conversion of Shares to Class A Common Stock								0	6	6
Compensation cost related to stock-based compensation	12,819	12,819
Excess tax benefits from stock-based compensation	6,198	6,198
Value of treasury stock repurchased	(4,186)				(4,186)
Stockholders' Equity, Other	(154)	(154)
Stockholders' Equity, Balance at Dec. 31, 2014	2,357,980	1,334,474	1,319,639	(72,252)	(224,547)	656	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME	225,037		225,037
Other comprehensive loss	(81,205)			(81,205)
Value of stock issued for stock-based compensation	6,829	6,826				3
Conversion of Shares to Class A Common Stock								$ 0	$ 2	$ 2	$ 0	$ (36)	$ 36
Compensation cost related to stock-based compensation	14,421	14,421
Excess tax benefits from stock-based compensation	1,432	1,432
Value of treasury stock repurchased	(3,261)				(3,261)
Stockholders' Equity, Other	(1,772)	(1,772)
Stockholders' Equity, Balance at Dec. 31, 2015	$ 2,519,461	$ 1,355,345	$ 1,544,676	$ (153,457)	$ (227,808)	$ 697	$ 8