Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2011	$ 195,640	$ 107	$ (1,924)	$ 62,745	$ 142,037	$ (7,325)
Beginning Balance (in shares) at Dec. 31, 2011		10,540,563
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	17,623				17,623
Other comprehensive income (loss), net of tax	(143)					(143)
Stock options exercised (in shares)		69,498
Stock options exercised	0	0		0
Stock repurchased related to the exercise of stock options (in shares)		(15,296)
Stock repurchased related to the exercise of stock options	(186)			(186)
Stock-based compensation	1,959			1,959
Income tax benefit (shortfall) related to the exercise of nonqualified stock options	324			324
Ending Balance at Dec. 31, 2012	215,217	107	(1,924)	64,842	159,660	(7,468)
Ending Balance (in shares) at Dec. 31, 2012		10,594,765
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	11,378				11,378
Other comprehensive income (loss), net of tax	3,606					3,606
Stock options exercised (in shares)		487,163
Stock options exercised	8,775	5		8,770
Stock repurchased related to the exercise of stock options (in shares)		(265,174)
Stock repurchased related to the exercise of stock options	(6,807)	(2)		(6,805)
Stock-based compensation	2,438			2,438
Income tax benefit (shortfall) related to the exercise of nonqualified stock options	(336)			(336)
Ending Balance at Dec. 31, 2013	234,271	110	(1,924)	68,909	171,038	(3,862)
Ending Balance (in shares) at Dec. 31, 2013		10,816,754
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	19,867				19,867
Other comprehensive income (loss), net of tax	(2,789)					(2,789)
Stock options exercised (in shares)	117,149	117,149
Stock options exercised	2,276	1		2,275
Stock repurchased related to the exercise of stock options (in shares)		(34,597)
Stock repurchased related to the exercise of stock options	(920)	(1)		(919)
Stock awards vested (in shares)		52,962
Stock awards vested	0	1		(1)
Stock-based compensation	3,725			3,725
Income tax benefit (shortfall) related to the exercise of nonqualified stock options	140			140
Retirement of treasury stock (in shares)		0
Retirement of treasury stock	0	(1)	1,924	(1,923)
Ending Balance at Dec. 31, 2014	$ 256,570	$ 110	$ 0	$ 72,206	$ 190,905	$ (6,651)
Ending Balance (in shares) at Dec. 31, 2014		10,952,268