CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2011	$ 22,119		$ 753,119	$ (12,646)	$ 762,592
Balance (in shares) at Dec. 31, 2011	221,188,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for stock incentive plans and other, net	152	11,105			11,257
Stock issued for stock incentive plans and other, net (in shares)	1,530,000
Stock purchased and retired	(201)	(13,885)	(16,515)		(30,601)
Stock purchased and retired (in shares)	(2,011,000)
Increased ownership interest in subsidiary, net of taxes			(5,507)		(5,507)
Net income			274,436		274,436
Pension adjustment, net of taxes				(1,707)	(1,707)
Foreign currency translation				265	265
Unrealized loss on securities, net of taxes				(158)	(158)
Dividends declared			(114,069)		(114,069)
Excess tax benefits for share- based payments		2,724			2,724
Three-for-two stock split	(56)	56
Three-for-two stock splits (in shares)	(563,000)
Balance at Dec. 31, 2012	22,014		891,464	(14,246)	899,232
Balance (in shares) at Dec. 31, 2012	220,144,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for stock incentive plans and other, net	70	8,107			8,177
Stock issued for stock incentive plans and other, net (in shares)	699,000
Stock purchased and retired	(185)	(11,285)	(13,652)		(25,122)
Stock purchased and retired (in shares)	(1,857,000)
Net income			166,895		166,895
Pension adjustment, net of taxes				4,928	4,928
Foreign currency translation				(778)	(778)
Unrealized loss on securities, net of taxes				(19)	(19)
Dividends declared			(87,789)		(87,789)
Excess tax benefits for share- based payments		3,178			3,178
Balance at Dec. 31, 2013	21,899		956,918	(10,115)	968,702
Balance (in shares) at Dec. 31, 2013	218,986,000				218,985,816
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for stock incentive plans and other, net	57	9,017			9,074
Stock issued for stock incentive plans and other, net (in shares)	569,000
Stock purchased and retired	(302)	(13,353)	(35,942)		(49,597)
Stock purchased and retired (in shares)	(3,016,000)
Net income			245,193		245,193
Pension adjustment, net of taxes				(6,486)	(6,486)
Foreign currency translation				(1,124)	(1,124)
Unrealized loss on securities, net of taxes				(108)	(108)
Dividends declared			(91,608)		(91,608)
Excess tax benefits for share- based payments		4,336			4,336
Balance at Dec. 31, 2014	$ 21,654		$ 1,074,561	$ (17,833)	$ 1,078,382
Balance (in shares) at Dec. 31, 2014	216,539,000				216,539,015