Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
BASIC
Net income	$ 8,488	$ 5,841	$ 12,761	$ 8,787
Weighted-average common shares outstanding (in shares)	15,784	15,098	15,785	15,032
Basic earnings per share (in dollars per share)	$ 0.54	$ 0.39	$ 0.81	$ 0.58
DILUTED
Net income	$ 8,488	$ 5,841	$ 12,761	$ 8,787
Weighted-average common shares outstanding (in shares)	15,784	15,098	15,785	15,032
Dilutive effect of stock options and restricted stock (in shares)	357	321	366	290
Weighted-average common shares outstanding on a diluted basis (in shares)	16,141	15,419	16,151	15,322
Diluted earnings per share (in dollars per share)	$ 0.53	$ 0.38	$ 0.79	$ 0.57