Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic and Diluted Earnings Per Share
Net income available to common stockholders, basic	$ 77,627	$ 63,444	$ 158,429	$ 106,783
Net income available to common stockholders, diluted	$ 77,627	$ 63,444	$ 158,429	$ 106,783
Average outstanding shares - basic (in shares)	95,505,877	95,405,493	95,485,839	94,346,582
Add: dilutive restricted stock units and stock options (in shares)	75,027	24,910	79,752	49,348
Average outstanding shares - diluted (in shares)	95,580,904	95,430,403	95,565,591	94,395,930
Basic earnings per share (in dollars per share)	$ 0.81	$ 0.67	$ 1.66	$ 1.13
Diluted earnings per share (in dollars per share)	$ 0.81	$ 0.66	$ 1.66	$ 1.13
Restricted stock units and stock options excluded from the diluted average outstanding share calculation (in shares)	0	143,938	0	121,533