Condensed Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2013	$ 250,946	$ 89,356	$ 159,733	$ 1,857
Beginning balance, shares at Dec. 31, 2013		16,076,662
Net income	7,365		7,365
Other comprehensive income (loss)	(55)			(55)
Stock option vesting	296	296
Stock options exercised	2,495	2,495
Stock options exercised, shares		144,020
Tax benefit of stock options exercised	184	184
Repurchase of common stock	(2,482)	(558)	(1,924)
Repurchase of common stock, shares		(100,385)
Dividends paid ($ 0.11 per share)	(1,772)		(1,772)
Ending balance at Mar. 31, 2014	256,977	91,773	163,402	1,802
Ending balance, shares at Mar. 31, 2014		16,120,297
Beginning balance at Dec. 31, 2014	418,172	244,318	176,057	(2,203)
Beginning balance, shares at Dec. 31, 2014	22,714,964	22,714,964
Net income	8,336		8,336
Other comprehensive income (loss)	120			120
Stock option vesting	220	220
RSU vesting	76	76
PSU vesting	28	28
Stock options exercised	887	887
Stock options exercised, shares	47,000	47,000
Tax benefit of stock options exercised	18	18
Repurchase of common stock	(509)	(231)	(278)
Repurchase of common stock, shares		(21,461)
Dividends paid ($ 0.11 per share)	(2,515)		(2,515)
Ending balance at Mar. 31, 2015	$ 424,833	$ 245,316	$ 181,600	$ (2,083)
Ending balance, shares at Mar. 31, 2015	22,740,503	22,740,503