Earnings Per Share - Reconciles Numerators and Denominators of Basic Earnings Per Share with Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator for Earnings per Share-Basic:
Net income	$ 22,721	$ 20,581	$ 63,674	$ 53,733
Less: Income allocated to participating shares	73	68	214	167
Net Income Allocated to Shareholders	22,648	20,513	63,460	53,566
Net Income Available to Shareholders	$ 22,721	$ 20,581	$ 63,674	$ 53,733
Denominators for Earnings per Share:
Weighted Average Shares Outstanding—Basic (in shares)	34,751,266	34,687,487	34,722,370	34,674,453
Add: Potentially dilutive shares (in shares)	208,873	81,018	208,139	72,724
Denominator for Treasury Stock Method—Diluted (in shares)	34,960,139	34,768,505	34,930,509	34,747,177
Weighted Average Shares Outstanding—Basic (in shares)	34,751,266	34,687,487	34,722,370	34,674,453
Add: Average participating shares outstanding (in shares)	111,821	114,746	116,969	108,414
Denominator for Two-Class Method—Diluted (in shares)	34,863,087	34,802,233	34,839,339	34,782,867
Earnings per share—basic (in dollars per share)	$ 0.65	$ 0.59	$ 1.83	$ 1.55
Earnings per share—diluted (in dollars per share)	0.65	0.59	1.82	1.54
Anti-dilutive warrants—exercise price (in dollars per share)	$ 31.53	$ 31.53	$ 31.53	$ 31.53
Warrants
Denominators for Earnings per Share:
Anti-dilutive excluded from potentially dilutive shares	443,575	517,012	452,188	517,012
Restricted Stock
Denominators for Earnings per Share:
Anti-dilutive excluded from potentially dilutive shares	92,577	146,695	95,707	134,983