CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2009	$ 4,975	$ 45,696	$ 92,401	$ (13,323)	$ (181)	$ 129,568
Net income			20,310			20,310
Cash dividends			(5,448)			(5,448)
Purchase of 14,520 shares				(467)		(467)
Other comprehensive income (loss):
Net unrealized loss on securities available for sale, net of tax					(2,149)	(2,149)
FASB ASC 715 adjustment, net of tax					(918)	(918)
Issuance of common shares pursuant to stock-based compensation plan, net		(349)		108		(241)
Exercise of stock options and SARs		(166)		133		(33)
Stock-based compensation expense		1,472				1,472
Balance at Dec. 31, 2010	4,975	46,653	107,263	(13,549)	(3,248)	142,094
Net income			23,009			23,009
Cash dividends			(6,279)			(6,279)
Stock dividend	470	33,643	(34,140)			(27)
Other comprehensive income (loss):
Net unrealized loss on securities available for sale, net of tax					7,268	7,268
Reclassification adjustments for gains included in net income, net of tax					(28)	(28)
FASB ASC 715 adjustment, net of tax					(6,713)	(6,713)
Issuance of common shares pursuant to stock-based compensation plan, net		(519)		436		(83)
Exercise of stock options and SARs		(196)		145		(51)
Stock-based compensation expense		1,390				1,390
Foreign currency translation					(32)	(32)
Balance at Dec. 31, 2011	5,445	80,971	89,853	(12,968)	(2,753)	160,548
Net income			23,303			23,303
Cash dividends			(7,361)			(7,361)
Stock dividend	521	44,280	(44,843)			(42)
Other comprehensive income (loss):
Net unrealized loss on securities available for sale, net of tax					1,756	1,756
Reclassification adjustments for gains included in net income, net of tax					(1,712)	(1,712)
FASB ASC 715 adjustment, net of tax					(3,384)	(3,384)
Issuance of common shares pursuant to stock-based compensation plan, net		(310)		392		82
Exercise of stock options and SARs		(1,254)		680		(574)
Stock-based compensation expense		1,399				1,399
Balance at Dec. 31, 2012	$ 5,966	$ 125,086	$ 60,952	$ (11,896)	$ (6,093)	$ 174,015