Consolidated Statements Of Changes In Shareholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2011	$ 218,876	$ 51,438	$ 165,377	$ 2,061
Beginning Balance (in shares) at Dec. 31, 2011		7,664,975
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	23,428		23,428
Other comprehensive income, net of tax	936			936
Stock-based compensation expense	538	538
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (in shares)		23,355
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit	(212)	(212)
Common stock repurchased (in shares)		(65,580)
Common stock repurchased	(2,097)	(2,097)
Cash dividends declared ($1.00, $1.08 and $1.11 per share in 2012, 2013, and 2014, respectively)	(7,654)		(7,654)
Ending Balance at Dec. 31, 2012	233,815	49,667	181,151	2,997
Ending Balance (in shares) at Dec. 31, 2012		7,622,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	22,783		22,783
Other comprehensive income, net of tax	(15,344)			(15,344)
Stock-based compensation expense	596	596
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (in shares)		25,308
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit	300	300
Common stock repurchased (in shares)		(68,145)
Common stock repurchased	(2,780)	(2,780)
Cash dividends declared ($1.00, $1.08 and $1.11 per share in 2012, 2013, and 2014, respectively)	(8,274)		(8,274)
Ending Balance at Dec. 31, 2013	231,096	47,783	195,660	(12,347)
Ending Balance (in shares) at Dec. 31, 2013		7,579,913
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	24,570		24,570
Other comprehensive income, net of tax	3,922			3,922
Stock-based compensation expense	599	599
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit (in shares)		27,664
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit	328	328
Common stock repurchased (in shares)		(181,355)
Common stock repurchased	(7,155)	(7,155)
Cash dividends declared ($1.00, $1.08 and $1.11 per share in 2012, 2013, and 2014, respectively)	(8,251)		(8,251)
Ending Balance at Dec. 31, 2014	$ 245,109	$ 41,555	$ 211,979	$ (8,425)
Ending Balance (in shares) at Dec. 31, 2014		7,426,222