Basis of Presentation - Schedule of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Basic earnings per share calculation:
Net income	$ 21,377	$ 8,388	$ 63,196	$ 29,380
Dividends paid on and undistributed earnings allocated to participating securities	(114)		(337)
Earnings attributable to common shareholders	$ 21,263	$ 8,388	$ 62,859	$ 29,380
Weighted-average basic shares outstanding	30,692,668	30,004,952	30,661,852	26,649,942
Basic earnings per share	$ 0.69	$ 0.28	$ 2.05	$ 1.10
Diluted earnings per share calculation:
Earnings attributable to common shareholders	$ 21,263	$ 8,388	$ 62,859	$ 29,380
Weighted-average basic shares outstanding	30,692,668	30,004,952	30,661,852	26,649,942
Weighted-average diluted shares contingently issuable	646,960	599,585	636,802	548,431
Weighted-average diluted shares outstanding	31,339,628	30,604,537	31,298,654	27,198,373
Diluted earnings per share	$ 0.68	$ 0.27	$ 2.01	$ 1.08