Earnings Per Common Share - Computation of basic and diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic earnings per common share:
Net income	$ 95,221	$ 51,565	$ 34,396	$ 137,392
Weighted-average basic common shares	70,905	34,057	49,330	34,859
Basic earnings per common share (in dollars per share)	$ 1.34	$ 1.51	$ 0.70	$ 3.94
Diluted earnings per share:
Net income	$ 95,221	$ 51,565	$ 34,396	$ 137,392
Weighted-average basic common shares	70,905	34,057	49,330	34,859
Effect of dilutive securities (in shares)	171	243	306	210
Weighted-average dilutive shares	71,076	34,300	49,636	35,069
Diluted earnings per common share (in dollars per share)	$ 1.34	$ 1.50	$ 0.69	$ 3.92