Consolidated Statements of Stockholders' Equity (unaudited) (USD $) In Thousands	Common Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Common Stock in Treasury [Member]	Total
Beginning Balance at Dec. 31, 2011	$ 380	$ 317,329	$ 329,981	$ (6,104)	$ (103,476)	$ 538,110
Net income	0	0	13,650	0	0	13,650
Cash dividends	0	0	(6,648)	0	0	(6,648)
Net issuance of shares to employee benefit plans and other stock plans, including tax benefit	0	(561)	(196)	0	1,742	985
Stock-based compensation	0	2,007	0	0	0	2,007
Other comprehensive income (loss)	0	0	0	629	0	629
Ending Balance at Mar. 31, 2012	380	318,775	336,787	(5,475)	(101,734)	548,733
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 income (loss)	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