Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Total Parent Equity [Member]	Non-Controlling Interest in Subsidiaries [Member]
Beginning balance at Dec. 31, 2014	$ 3,312,364	$ 153,113	$ 26,414	$ (720,211)	$ 3,841,932	$ 3,301,248	$ 11,116
Beginning balance (in shares) at Dec. 31, 2014		153,113,042
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	705,672				705,672	705,672
Other comprehensive (loss) income, net of tax	(210,407)			(210,407)		(210,407)
Cash dividends declared	(372,840)				(372,840)	(372,840)
Share-based awards exercised, including tax benefit	(2,548)	$ 230	(2,778)			(2,548)
Share-based awards exercised, including tax benefit (in shares)		229,958
Share-based compensation	17,717		17,717			17,717
Purchase of stock	(292,275)	$ (3,262)			(289,013)	(292,275)
Purchase of stock (in shares)		(3,261,526)
Noncontrolling interest activities	1,559						1,559
Ending balance at Dec. 31, 2015	3,159,242	$ 150,081	41,353	(930,618)	3,885,751	3,146,567	12,675
Ending balance (in shares) at Dec. 31, 2015		150,081,474
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	687,240				687,240	687,240
Other comprehensive (loss) income, net of tax	(82,403)			(82,403)		(82,403)
Cash dividends declared	(391,852)				(391,852)	(391,852)
Share-based awards exercised, including tax benefit	(4,126)	$ 341	(4,467)			(4,126)
Share-based awards exercised, including tax benefit (in shares)		340,703
Share-based compensation	19,719		19,719			19,719
Purchase of stock	(181,417)	$ (2,012)			(179,405)	(181,417)
Purchase of stock (in shares)		(2,011,755)
Noncontrolling interest activities	953						953
Ending balance at Dec. 31, 2016	3,207,356	$ 148,410	56,605	(1,013,021)	4,001,734	3,193,728	13,628
Ending balance (in shares) at Dec. 31, 2016		148,410,422
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	616,757				616,757	616,757
Other comprehensive (loss) income, net of tax	160,429			160,429		160,429
Cash dividends declared	(396,891)				(396,891)	(396,891)
Share-based awards exercised, including tax benefit	$ (5,239)	$ 132	(5,371)			(5,239)
Share-based awards exercised, including tax benefit (in shares)	348,000	131,232
Share-based compensation	$ 16,892		16,892			16,892
Purchase of stock	(173,524)	$ (1,889)			(171,635)	(173,524)
Purchase of stock (in shares)		(1,889,039)
Noncontrolling interest activities	38,376						38,376
Ending balance at Dec. 31, 2017	$ 3,464,156	$ 146,653	$ 68,126	$ (852,592)	$ 4,049,965	$ 3,412,152	$ 52,004
Ending balance (in shares) at Dec. 31, 2017		146,652,615