Earnings Per Share ("EPS") (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income available to common stockholders	$ 80,561	$ 65,885	$ 222,879	$ 201,897
Average common shares outstanding (in shares)	107,822	109,019	108,130	110,292
Average potential dilutive common shares (in shares)	538	189	538	189
Average diluted common shares (in shares)	108,360	109,208	108,668	110,481
Basic earnings per share (in dollars per share)	$ 0.75	$ 0.60	$ 2.06	$ 1.83
Diluted earnings per share (in dollars per share)	$ 0.74	$ 0.60	$ 2.05	$ 1.83