Basis of Presentation - Schedule of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic earnings per share calculation:
Net income	$ 22,065	$ 11,239	$ 41,819	$ 20,992
Dividends paid on and undistributed earnings allocated to participating securities	(117)		(223)
Earnings attributable to common shareholders	$ 21,948	$ 11,239	$ 41,596	$ 20,992
Weighted-average basic shares outstanding	30,678,732	25,741,968	30,646,189	24,944,633
Basic earnings per share	$ 0.72	$ 0.44	$ 1.36	$ 0.84
Diluted earnings per share:
Earnings attributable to common shareholders	$ 21,948	$ 11,239	$ 41,596	$ 20,992
Weighted-average basic shares outstanding	30,678,732	25,741,968	30,646,189	24,944,633
Weighted-average diluted shares contingently issuable	615,312	559,490	629,657	505,786
Weighted-average diluted shares outstanding	31,294,044	26,301,458	31,275,846	25,450,419
Diluted earnings per share	$ 0.70	$ 0.43	$ 1.33	$ 0.82