CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) - 3 months ended Mar. 31, 2017 - USD ($) shares in Thousands, $ in Thousands	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2016	$ 21,749		$ 803,152	$ (18,102)	$ 806,799
Balance (in shares) at Dec. 31, 2016	217,489
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued for stock incentive plans, net	$ 55	2,632			2,687
Stock issued for stock incentive plans, net (in shares)	550
Stock purchased and retired	$ (26)	$ (2,632)	(3,016)		(5,674)
Stock purchased and retired (in shares)	(259)
Net income			3,634		3,634
Pension adjustment, net of taxes				135	135
Foreign currency translation				42	42
Unrealized loss on securities, net of taxes				(15)	(15)
Balance at Mar. 31, 2017	$ 21,778		$ 803,770	$ (17,940)	$ 807,608
Balance (in shares) at Mar. 31, 2017	217,780