Stockholders' Equity - Reconciliation of Weighted Average Shares (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income:
Net income	$ 11,828	$ 8,895	$ 21,144	$ 17,986
Less: Dividends and undistributed earnings allocated to participating securities	(83)	(91)	(164)	(177)
Net income allocated to common shareholders	$ 11,745	$ 8,804	$ 20,980	$ 17,809
Basic:
Weighted average common shares outstanding (in shares)	29,939,280	29,976,644	29,945,641	29,970,947
Less: Restricted stock awards (in shares)	(183,082)	(307,786)	(215,446)	(300,584)
Total basic weighted average common shares outstanding (in shares)	29,756,198	29,668,858	29,730,195	29,670,363
Diluted:
Basic weighted average common shares outstanding (in shares)	29,756,198	29,668,858	29,730,195	29,670,363
Incremental shares from stock options (in shares)	83,411	12,225	64,042	13,230
Total diluted weighted average common shares outstanding (in shares)	29,839,609	29,681,083	29,794,237	29,683,593