Earnings Per Share (Details 1) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	$ 415	$ 237	$ 671	$ 686
Participating Securities, Distributed and Undistributed Earnings of Net Income, Percent	0.72%	0.86%	0.72%	0.82%
Earnings per share – Basic:
Net income	$ 57,431	$ 27,437	$ 92,754	$ 83,729
Earnings available to common shareholders – Basic	$ 57,016	$ 27,200	$ 92,083	$ 83,043
Weighted-average common shares outstanding – Basic	78,237,199	77,989,933	78,197,091	78,230,011
Earnings per common share – Basic	$ 0.73	$ 0.35	$ 1.18	$ 1.06
Earnings per share – Diluted:
Net income	$ 57,431	$ 27,437	$ 92,754	$ 83,729
Earnings available to common shareholders – Diluted	$ 57,016	$ 27,200	$ 92,083	$ 83,043
Weighted-average common shares outstanding – Basic	78,237,199	77,989,933	78,197,091	78,230,011
Effect of dilutive shares(2)	137,810	32,235	169,053	35,804
Weighted-average common shares outstanding – Diluted	78,375,009	78,022,168	78,366,144	78,265,815
Earnings per common share – Diluted	$ 0.73	$ 0.35	$ 1.18	$ 1.06