CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Non- controlling Interests subject to put provisions	Common stock	Common stock Stock Appreciation Rights	Additional paid-in capital	Additional paid-in capital Stock Appreciation Rights	Retained earnings	Treasury stock	Treasury stock Stock Appreciation Rights	Accumulated other comprehensive income (loss)	Total	Total Stock Appreciation Rights	Non-controlling interests not subject to put provisions
Beginning Balance at Dec. 31, 2012		$ 580,692	$ 270		$ 1,208,665		$ 3,731,835	$ (1,162,336)		$ (15,297)	$ 3,763,137		$ 153,788
Beginning Balance (in shares) at Dec. 31, 2012			269,725,000					(58,728,000)
Comprehensive income:
Net income		78,215					633,446				633,446		45,540
Other comprehensive income (loss)	$ 12,652									12,652	12,652
Stock purchase shares issued					12,817						12,817
Stock purchase shares issued (in shares)			238,000
Stock-settled shares issued					(3,286)	$ (29,025)		$ 3,247	$ 28,561		(39)	$ (464)
Stock-settled shares issued (in shares)			7,000	313,000				164,000	1,444,000
Stock-based compensation expense					59,998						59,998
Excess tax benefits from stock awards exercised					36,197						36,197
Distributions to noncontrolling interests		(80,353)											(58,973)
Contributions from noncontrolling interests		22,053											14,943
Sales and assumptions of additional noncontrolling interests		23,642			(1,442)						(1,442)		10,770
Purchases from noncontrolling interests		(512)			(3,119)						(3,119)		(147)
Expiration of put option and other reclassification		(7,141)											7,141
Changes in fair value of noncontrolling interests		80,704			(80,704)						(80,704)
Treasury stock retirement			$ (57)		(129,179)		(1,001,292)	$ 1,130,528
Treasury stock retirement (Shares)			(57,120,000)					57,120,000
Ending Balance at Dec. 31, 2013		697,300	$ 213		1,070,922		3,363,989			(2,645)	4,432,479		173,062
Ending Balance (in shares) at Dec. 31, 2013			213,163,000
Comprehensive income:
Purchase of treasury stock (in shares)	0
Net income		88,425					723,114				723,114		51,791
Other comprehensive income (loss)	$ (22,372)									(22,372)	(22,372)
Stock purchase shares issued					19,010						19,010
Stock purchase shares issued (in shares)			298,000
Stock-settled shares issued			$ 1	$ 2	(28)	(2)					(27)
Stock-settled shares issued (in shares)			304,000	1,876,000
Stock-based compensation expense					54,969						54,969
Excess tax benefits from stock awards exercised					45,271						45,271
Distributions to noncontrolling interests		(93,884)											(55,455)
Contributions from noncontrolling interests		41,876											22,779
Sales and assumptions of additional noncontrolling interests		25,220			355						355		4,165
Purchases from noncontrolling interests		(6,111)			(5,357)						(5,357)		(6,544)
Other reclassification					210						210
Changes in fair value of noncontrolling interests		77,139			(77,139)						(77,139)
Ending Balance at Dec. 31, 2014	$ 5,360,311	829,965	$ 216		1,108,211		4,087,103			(25,017)	5,170,513		189,798
Ending Balance (in shares) at Dec. 31, 2014	215,640,968		215,641,000
Comprehensive income:
Purchase of treasury stock (in shares)	0
Net income		96,510					269,732				269,732		61,168
Other comprehensive income (loss)	$ (34,809)									(34,809)	(34,809)
Stock purchase shares issued					(6,079)			$ 30,608			24,529
Stock purchase shares issued (in shares)								414,000
Stock-settled shares issued				$ 1		$ (1)
Stock-settled shares issued (in shares)			348,000	1,131,000
Stock-based compensation expense					56,899						56,899
Excess tax benefits from stock awards exercised					28,157						28,157
Distributions to noncontrolling interests		(103,355)											(71,280)
Contributions from noncontrolling interests		25,795											28,849
Sales and assumptions of additional noncontrolling interests		10,654											6,875
Purchases from noncontrolling interests		(8,538)			(55,826)						(55,826)		(2,018)
Changes in fair value of noncontrolling interests		13,035			(13,035)						(13,035)
Ending Balance at Dec. 31, 2015	$ 5,084,172	$ 864,066	$ 217		$ 1,118,326		$ 4,356,835	$ (544,772)		$ (59,826)	4,870,780		$ 213,392
Ending Balance (in shares) at Dec. 31, 2015	209,754,247		217,120,000					(7,366,000)
Comprehensive income:
Purchase of treasury stock	$ (575,380)							$ (575,380)			$ (575,380)
Purchase of treasury stock (in shares)	(7,779,958)							(7,780,000)