Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net income	$ 8,074	$ 7,741	$ 15,246	$ 14,013
Less: Net income allocated to participating securities	(32)	(54)	(96)	(116)
Net income available to common shareholders	$ 8,042	$ 7,687	$ 15,150	$ 13,897
Denominator:
Weighted average common shares outstanding	20,760	21,115	20,662	21,108
Weighted average dilutive securities	455	516	473	492
Weighted average common shares outstanding, diluted	21,215	21,631	21,135	21,600
Income per common share, basic (in dollars per share)	$ 0.39	$ 0.36	$ 0.73	$ 0.66
Income per common share, diluted (in dollars per share)	$ 0.38	$ 0.36	$ 0.72	$ 0.64