CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interests	Redeemable Noncontrolling Interest	Total
Balances at Dec. 31, 2015	$ 638	$ (396,455)	$ 1,110,253	$ 1,965,291		$ (134,616)	$ 126,340	$ 2,545,111
Common Stock, Shares, Outstanding, Beginning Balance at Dec. 31, 2015	243,090,000
Treasury Stock, Shares, Beginning Balance at Dec. 31, 2015		19,848,000
Proceeds from exercise of stock options, including related tax effect	$ 3		9,834					9,837
Proceeds from exercise of stock options, including related tax effect (in shares)	556,000	12,000
Dividends declared				(136,472)				(136,472)
Noncontrolling investors, net				(356)		7,164	(15,100)	6,808
Share repurchases		$ (25,034)						$ (25,034)
Share repurchases (in shares)	(732,000)	732,000						732,000
Equity-based compensation		$ 4,660	12,662	(119)				$ 17,203
Equity-based compensation (in shares)	871,000	(247,000)
Comprehensive and net income (loss)				382,115		(22,109)		360,006
Net income								360,006
Balances at Dec. 31, 2016	$ 641	$ (416,829)	1,132,749	2,210,459		(149,561)	111,240	2,777,459
Common Stock, Shares, Outstanding, Ending Balance at Dec. 31, 2016	243,785,000
Treasury Stock, Shares, Ending Balance at Dec. 31, 2016		20,345,000
Dividends declared				(148,231)				(148,231)
Share repurchases		$ (252,242)						$ (252,242)
Share repurchases (in shares)	(7,439,000)	7,439,000						7,400,000
Equity-based compensation	$ 3	$ 3,774	8,785	(276)				$ 12,286
Equity-based compensation (in shares)	1,051,000	(178,000)
Comprehensive and net income (loss)				812,741		(6,945)		805,796
Net income								805,796
Balances at Dec. 31, 2017	$ 644	$ (665,297)	1,141,534	2,874,693		(156,506)	111,240	$ 3,195,068
Common Stock, Shares, Outstanding, Ending Balance at Dec. 31, 2017	237,397,000							237,396,839
Treasury Stock, Shares, Ending Balance at Dec. 31, 2017		27,606,000						27,606,294
Dividends declared				(174,355)				$ (174,355)
Noncontrolling investors, net						(2)		(2)
Share repurchases		$ (523,569)						$ (523,569)
Share repurchases (in shares)	(13,129,000)	13,129,000						13,100,000
Equity-based compensation	$ 1	$ 4,623	18,514	(397)				$ 22,741
Equity-based compensation (in shares)	1,004,000	(185,000)
Comprehensive and net income (loss)								1,256,106
Net income				1,258,379		(2,574)		1,255,805
Other comprehensive income, net of tax					$ 301			301
Balances at Dec. 31, 2018	$ 645	$ (1,184,243)	$ 1,160,048	$ 3,958,320	$ 301	$ (159,082)	$ 111,240	$ 3,775,989
Common Stock, Shares, Outstanding, Ending Balance at Dec. 31, 2018	225,272,000							225,272,174
Treasury Stock, Shares, Ending Balance at Dec. 31, 2018		40,550,000						40,550,228