CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Capital In Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2013	$ 47,872	$ 87,563	$ 228,036	$ 1,786	$ (15,825)	$ 349,432
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	11,725	0	0	11,725
Other comprehensive income (loss), net of tax	0	0	0	(716)	0	(716)
Cash dividends paid	0	0	(2,984)	0	0	(2,984)
Purchase of treasury stock	0	0	0	0	(4,526)	(4,526)
Stock-based compensation and related tax benefits	0	929	0	0	79	1,008
Stock options exercised and related tax benefits	0	(16)	0	0	82	66
Employee Stock Ownership Plan	0	826	0	0	1,000	1,826
Balance at Mar. 31, 2014	$ 47,872	$ 89,302	$ 236,777	$ 1,070	$ (19,190)	$ 355,831