CONSOLIDATED STATEMENTS OF EQUITY (unaudited) - USD ($) $ in Thousands	Total	Total	Total Restricted Stock Units	Total Stock Appreciation Rights	Non- controlling Interests subject to put provisions	Common stock	Common stock Restricted Stock Units	Common stock Stock Appreciation Rights	Additional paid-in capital	Additional paid-in capital Restricted Stock Units	Additional paid-in capital Stock Appreciation Rights	Retained earnings	Treasury stock	Treasury stock Restricted Stock Units	Treasury stock Stock Appreciation Rights	Accumulated other comprehensive(loss)	Non-controlling interests not subject to put provisions
Beginning balance at Dec. 31, 2015		$ 4,870,780			$ 864,066	$ 217			$ 1,118,326			$ 4,356,835	$ (544,772)			$ (59,826)	$ 213,392
Beginning Balance (in shares) at Dec. 31, 2015						217,120,000							(7,366,000)
Comprehensive income:
Other comprehensive (loss) income	$ 6,313
Beginning balance at Dec. 31, 2015		4,870,780			864,066	$ 217			1,118,326			4,356,835	$ (544,772)			(59,826)	213,392
Beginning Balance (in shares) at Dec. 31, 2015						217,120,000							(7,366,000)
Comprehensive income:
Net income		879,874			99,834							879,874					53,374
Other comprehensive (loss) income		(29,817)														(29,817)	190
Stock purchase shares issued		23,903				$ 1			23,902
Stock purchase shares issued (in shares)						438,000							0
Stock unit shares issued/settled			$ 0	$ 0			$ 0	$ 0		$ (19,815)	$ 36,685			$ 19,815	$ (36,685)
Stock unit shares issued/settled (in shares)							4,000	218,000						276,000	513,000
Stock-settled stock-based compensation expense		37,970							37,970
Excess tax benefits from stock awards exercised		13,251							13,251
Distributions to noncontrolling interests					(111,092)												(81,309)
Contributions from noncontrolling interests					33,517												14,073
Sales and assumptions of noncontrolling interests		3,423			28,874				3,423								2,585
Purchase of noncontrolling interests		(13,105)			(6,660)				(13,105)								(1,747)
Changes in fair value of noncontrolling interests		(65,855)			65,855				(65,855)
Reclassifications and expirations of noncontrolling interests subject to puts					(1,136)												1,136
Purchase of treasury stock		(1,072,377)											$ (1,072,377)
Purchase of treasury stock (in shares)													(16,649,000)
Retirement of treasury stock		0				$ (23)			(34,230)			(1,526,396)	$ 1,560,649
Retirement of treasury stock (in shares)						(23,226,000)							23,226,000
Ending balance at Dec. 31, 2016	$ 4,849,741	4,648,047			973,258	$ 195			1,027,182			3,710,313	$ 0			(89,643)	201,694
Ending Balance (in shares) at Dec. 31, 2016	194,554,491					194,554,000							0
Comprehensive income:
Net income		447,697			34,585							447,697					18,003
Other comprehensive (loss) income	$ 12,755	12,757														12,757	(2)
Stock unit shares issued/settled			$ 0	$ 0			$ 0	$ 0		$ 0	$ 0			$ 0	$ 0
Stock unit shares issued/settled (in shares)							4,000	38,000						0	0
Stock-settled stock-based compensation expense		9,567							9,567
Distributions to noncontrolling interests		0			(25,957)												(17,359)
Contributions from noncontrolling interests		0			13,193												4,796
Sales and assumptions of noncontrolling interests		0			7,347				0								(6,388)
Purchase of noncontrolling interests		(423)			(294)				(423)								(82)
Changes in fair value of noncontrolling interests		22,284			(22,284)				22,284
Ending balance at Mar. 31, 2017	$ 5,340,591	$ 5,139,929			$ 979,848	$ 195			$ 1,058,610			$ 4,158,010	$ 0			$ (76,886)	$ 200,662
Ending Balance (in shares) at Mar. 31, 2017	194,596,120					194,596,000							0