CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Noncontrolling Interests	Redeemable Noncontrolling Interest	Total
Balances at Dec. 31, 2012	$ 637	$ (720,479)	$ 1,037,687	$ 2,087,620	$ (27,623)	$ 98,814	$ 2,377,842
Balances (in shares) at Dec. 31, 2012	219,523,000
Balances (in shares) at Dec. 31, 2012		36,070,000
Increase (Decrease) in Stockholders' Equity
Proceeds from exercise of stock options, including related tax effect (in shares)	3,132,000
Proceeds from exercise of stock options, including related tax effect	$ 8	$ (160)	37,660				37,508
Dividends declared				(97,375)			(97,375)
Conversion of 5.125% convertible senior notes		4					4
Acquisition of noncontrolling interest			(2,232)		2,232
Contributions from noncontrolling investors					160	17,700	160
Distributions to noncontrolling investors					(439)		(439)
Equity-based compensation		$ 2,106	12,579	(46)			14,639
Equity-based compensation (in shares)	212,000	(97,000)
Comprehensive income and net income (loss)				189,314	(25,798)		163,516
Balances at Dec. 31, 2013	$ 645	$ (718,529)	1,085,694	2,179,513	(51,468)	116,514	2,495,855
Balances (in shares) at Dec. 31, 2013	222,867,000
Balances (in shares) at Dec. 31, 2013		35,973,000
Increase (Decrease) in Stockholders' Equity
Proceeds from exercise of stock options, including related tax effect (in shares)	1,770,000	8,000
Proceeds from exercise of stock options, including related tax effect	$ 5	$ (164)	32,466				32,307
Dividends declared				(108,630)			(108,630)
Conversion of 5.125% convertible senior notes		$ 317,451	(45,650)				271,801
Conversion of 5.125% convertible senior notes (in shares)	15,893,000	(15,893,000)
Contributions from noncontrolling investors					97	9,826	97
Distributions to noncontrolling investors					(743)		(743)
Equity-based compensation	$ (15)	$ 2,344	10,925	(64)			13,190
Equity-based compensation (in shares)	919,000	(117,000)
Comprehensive income and net income (loss)				157,024	(65,374)		91,650
Balances at Dec. 31, 2014	$ 635	$ (398,898)	1,083,435	2,227,843	(117,488)	126,340	$ 2,795,527
Balances (in shares) at Dec. 31, 2014	241,449,000						241,449,423
Balances (in shares) at Dec. 31, 2014		19,971,000					19,970,703
Increase (Decrease) in Stockholders' Equity
Proceeds from exercise of stock options, including related tax effect (in shares)	737,000	10,000
Proceeds from exercise of stock options, including related tax effect	$ 1	$ (211)	10,975				$ 10,765
Dividends declared				(133,227)			(133,227)
Dissolution of noncontrolling interest				1,082	(1,082)
Distributions to noncontrolling investors					(1,187)		(1,187)
Equity-based compensation	$ 2	$ 2,654	15,843	(96)			18,403
Equity-based compensation (in shares)	904,000	(133,000)
Comprehensive income and net income (loss)				(130,311)	(14,859)		(145,170)
Balances at Dec. 31, 2015	$ 638	$ (396,455)	$ 1,110,253	$ 1,965,291	$ (134,616)	$ 126,340	$ 2,545,111
Balances (in shares) at Dec. 31, 2015	243,090,000						243,089,514
Balances (in shares) at Dec. 31, 2015		19,848,000					19,847,625