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
	Mar. 31, 2018	Mar. 31, 2017
Numerator for Earnings per Share Basic and Diluted:
Net income	$ 26,163	$ 18,188
Less: Income allocated to participating shares	80	60
Net Income Allocated to Shareholders	26,083	18,128
Net Income Available to Shareholders	$ 26,163	$ 18,188
Denominators for Earnings per Share:
Weighted Average Shares Outstanding—Basic (in shares)	34,756,726	34,690,250
Add: Potentially dilutive shares (in shares)	242,439	222,011
Denominator for Treasury Stock Method—Diluted (in shares)	34,999,165	34,912,261
Weighted Average Shares Outstanding—Basic (in shares)	34,756,726	34,690,250
Add: Average participating shares outstanding (in shares)	106,722	115,395
Denominator for Two-Class Method—Diluted (in shares)	34,863,448	34,805,645
Earnings per share—basic (in dollars per share)	$ 0.75	$ 0.52
Earnings per share—diluted (in dollars per share)	0.75	0.52
Anti-dilutive warrants—exercise price (in dollars per share)	$ 31.53	$ 31.53
Warrants
Denominators for Earnings per Share:
Anti-dilutive excluded from potentially dilutive shares (in shares)	400,722	447,103
Restricted Stock
Denominators for Earnings per Share:
Anti-dilutive excluded from potentially dilutive shares (in shares)	90,298	79,544