Earnings per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	10,533
Numerator:
Net income (loss) attributable to common shareholders	$ 31,631	$ 23,737	$ 52,290	$ 38,325
Less: dividends paid on unvested share-based compensation	(109)	(125)	(323)	(375)
Undistributed Earnings Attributable to Share-Based Compensation	(45)	(63)	0	0
Net income (loss) available to common shareholders	$ 31,477	$ 23,549	$ 51,967	$ 37,950
Denominator:
Weighted-average number of common shares-basic	71,735,129	64,859,494	71,709,380	64,133,134
Effect of dilutive share-based compensation	716,181	486,694	783,533	480,315
Weighted-average number of common shares-diluted	72,451,310	65,346,188	72,492,913	64,613,449
Net income (loss) per share available to common shareholders-basic (in dollars per share)	$ 0.44	$ 0.36	$ 0.72	$ 0.59
Net income (loss) per share available to common shareholders-diluted (usd per share)	$ 0.43	$ 0.36	$ 0.72	$ 0.59