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, 2013	$ 21,899		$ 956,918	$ (10,115)	$ 968,702
Balance (in shares) at Dec. 31, 2013	218,986
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for stock incentive plans, net	61	2,259			2,320
Stock issued for stock incentive plans, net (in shares)	611
Stock purchased and retired	(76)	(6,714)	(6,354)		(13,144)
Stock purchased and retired (in shares)	(753)
Net income			39,388		39,388
Pension adjustment, net of taxes				84	84
Foreign currency translation				(471)	(471)
Unrealized loss on securities, net of taxes				(36)	(36)
Dividends declared			(22,986)		(22,986)
Excess tax benefits for share- based payments		4,455			4,455
Balance at Mar. 31, 2014	$ 21,884		$ 966,966	$ (10,538)	$ 978,312
Balance (in shares) at Mar. 31, 2014	218,844