CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) (USD $) In Thousands, unless otherwise specified	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2012	$ 22,014		$ 891,464	$ (14,246)	$ 899,232
Balance (in shares) at Dec. 31, 2012	220,144
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for stock incentive plans, net	76	4,175			4,251
Stock issued for stock incentive plans, net (in shares)	756
Stock purchased and retired	(154)	(7,372)	(13,059)		(20,585)
Stock purchased and retired (in shares)	(1,544)
Net income			75,492		75,492
Pension adjustment, net of taxes				248	248
Foreign currency translation				(627)	(627)
Unrealized loss on securities, net of taxes				(31)	(31)
Dividends declared			(44,030)		(44,030)
Excess tax benefits for share- based payments		3,197			3,197
Balance at Jun. 30, 2013	$ 21,936		$ 909,867	$ (14,656)	$ 917,147
Balance (in shares) at Jun. 30, 2013	219,356