Consolidated Statements of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Total shareholders' equity	Noncontrolling interest
Balance at Dec. 31, 2011	$ 2,010,069	$ 2,120	$ 13,260	$ 1,991,222	$ (2,964)	$ 2,003,638	$ 6,431
Balance (in shares) at Dec. 31, 2011		212,003,662
Increase (Decrease) in Equity [Roll Forward]
Exercise of stock options and release of restricted shares (in shares)		1,653,994
Exercise of stock options and release of restricted shares	29,119	16	29,103			29,119
Issuance of shares under stock purchase plan (in shares)		773,661
Issuance of shares under stock purchase plan	23,392	8	23,384			23,392
Shares repurchased under provisions of stock repurchase plans (in shares)		(8,039,304)
Shares repurchased under provisions of stock repurchase plans	(302,414)	(80)	(113,633)	(188,701)		(302,414)
Stock compensation expense	44,058		44,058			44,058
Tax benefits from stock plans, net	5,111		5,111			5,111
Net earnings	332,969			333,360		333,360	(391)
Other comprehensive (loss) income	8,811				8,698	8,698	113
Dividends paid	(117,263)			(117,263)		(117,263)
Distributions of dividends to noncontrolling interest	(1,282)						(1,282)
Balance at Dec. 31, 2012	2,032,570	2,064	1,283	2,018,618	5,734	2,027,699	4,871
Balance (in shares) at Dec. 31, 2012		206,392,013
Increase (Decrease) in Equity [Roll Forward]
Exercise of stock options and release of restricted shares (in shares)		1,509,890
Exercise of stock options and release of restricted shares	35,775	15	35,760			35,775
Issuance of shares under stock purchase plan (in shares)		800,461
Issuance of shares under stock purchase plan	23,977	8	23,969			23,977
Shares repurchased under provisions of stock repurchase plans (in shares)		(6,149,144)
Shares repurchased under provisions of stock repurchase plans	(261,936)	(62)	(105,398)	(156,476)		(261,936)
Stock compensation expense	43,813		43,813			43,813
Tax benefits from stock plans, net	2,174		2,174			2,174
Net earnings	350,011			348,526		348,526	1,485
Other comprehensive (loss) income	(12,420)				(11,999)	(11,999)	(421)
Dividends paid	(123,292)			(123,292)		(123,292)
Purchase of noncontrolling interest	(3,180)		46			46	(3,226)
Distributions of dividends to noncontrolling interest	(1,161)						(1,161)
Balance at Dec. 31, 2013	2,086,331	2,025	1,647	2,087,376	(6,265)	2,084,783	1,548
Balance (in shares) at Dec. 31, 2013	202,553,220	202,553,220
Increase (Decrease) in Equity [Roll Forward]
Exercise of stock options and release of restricted shares (in shares)		1,528,758
Exercise of stock options and release of restricted shares	45,469	15	45,454			45,469
Issuance of shares under stock purchase plan (in shares)		671,775
Issuance of shares under stock purchase plan	23,800	7	23,793			23,800
Shares repurchased under provisions of stock repurchase plans (in shares)		(13,098,063)
Shares repurchased under provisions of stock repurchase plans	(550,781)	(131)	(114,216)	(436,434)		(550,781)
Stock compensation expense	42,533		42,533			42,533
Tax benefits from stock plans, net	1,061		1,061			1,061
Net earnings	379,460			376,888		376,888	2,572
Other comprehensive (loss) income	(31,969)				(31,552)	(31,552)	(417)
Dividends paid	(124,634)			(124,634)		(124,634)
Purchase of noncontrolling interest	841		841			841	0
Distributions of dividends to noncontrolling interest	(503)						(503)
Balance at Dec. 31, 2014	$ 1,871,608	$ 1,916	$ 1,113	$ 1,903,196	$ (37,817)	$ 1,868,408	$ 3,200
Balance (in shares) at Dec. 31, 2014	191,655,690	191,655,690