UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2011	$ 22,043	$ 175,616	$ 0	$ 197,659
Balance (in shares) at Dec. 31, 2011	23,838
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	16,303	0	16,303
Other comprehensive income (loss), net of tax	0	0	(863)	(863)
Dividends declared	0	(7,896)	0	(7,896)
Dividends reinvested in common stock	493	0	0	493
Dividends reinvested in common stock (in shares)	37
Stock based compensation	1,842	0	0	1,842
Common stock issued through exercise of incentive stock options	404	0	0	404
Common stock issued through exercise of incentive stock options (in shares)	55
Common stock issued for share awards	0	0	0	0
Common stock issued for share awards (in shares)	45
Common stock issued	10	0	0	10
Common stock issued (in shares)	1
Common stock repurchased	(143)	0	0	(143)
Common stock repurchased (in shares)	(13)
Net excess tax benefit from stock options exercised	39	0	0	39
Balance at Dec. 31, 2012	24,688	184,023	(863)	207,848
Balance (in shares) at Dec. 31, 2012	23,962
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	8,351	0	8,351
Other comprehensive income (loss), net of tax	0	0	532	532
Stock based compensation	425	0	0	425
Common stock issued for share awards	0	0	0	0
Common stock issued for share awards (in shares)	37
Common stock issued	2	0	0	2
Common stock issued (in shares)	0
Common stock repurchased	(155)	0	0	(155)
Common stock repurchased (in shares)	(11)
Net excess tax benefit from stock options exercised	13	0	0	13
Balance at Mar. 31, 2013	$ 24,973	$ 192,374	$ (331)	$ 217,016
Balance (in shares) at Mar. 31, 2013	23,988