Consolidated Statements of Stockholders' Equity (unaudited) (USD $) In Thousands	Common Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Common Stock in Treasury [Member]	Total
Beginning Balance at Dec. 31, 2012	$ 393	$ 346,692	$ 357,558	$ (5,880)	$ (116,490)	$ 582,273
Net income	0	0	7,649	0	0	7,649
Cash dividends	0	0	(6,758)	0	0	(6,758)
Net issuance of shares for acquisition	104	225,447	0	0	(5,779)	219,772
Net issuance of shares to employee benefit plans and other stock plans, including tax benefit	0	(965)	0	0	606	(359)
Stock-based compensation	0	1,964	0	0	0	1,964
Other comprehensive (loss) income	0	0	0	(1,246)	0	(1,246)
Ending Balance at Mar. 31, 2013	497	573,138	358,449	(7,126)	(121,663)	803,295
Beginning Balance at Dec. 31, 2013	497	574,152	385,787	(16,765)	(127,102)	816,569
Net income	0	0	18,009	0	0	18,009
Cash dividends	0	0	(9,207)	0	0	(9,207)
Net issuance of shares to employee benefit plans and other stock plans, including tax benefit	0	(1,335)	0	0	1,697	362
Stock-based compensation	0	1,254	0	0	0	1,254
Other comprehensive (loss) income	0	0	0	5,215	0	5,215
Ending Balance at Mar. 31, 2014	$ 497	$ 574,071	$ 394,589	$ (11,550)	$ (125,405)	$ 832,202