Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic and Diluted Earnings Per Share
Net income available to common stockholders, basic	$ 75,619	$ 77,757	$ 234,048	$ 184,540
Net income available to common stockholders, diluted	$ 75,619	$ 77,757	$ 234,048	$ 184,540
Average outstanding shares - basic (in shares)	95,510,772	95,411,656	95,494,211	94,704,198
Add: dilutive restricted stock units and stock options (in shares)	75,430	30,920	79,308	43,696
Average outstanding shares - diluted (in shares)	95,586,202	95,442,576	95,573,519	94,747,894
Basic earnings per share (in dollars per share)	$ 0.79	$ 0.81	$ 2.45	$ 1.95
Diluted earnings per share (in dollars per share)	$ 0.79	$ 0.81	$ 2.45	$ 1.95
Restricted stock units and stock options excluded from the diluted average outstanding share calculation (in shares)	0	93,253	0	78,605