Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Net income	$ 83,248	$ 87,154	$ 103,360	$ 96,275	$ 86,824	$ 74,262	$ 273,762	$ 257,360
Preferred stock dividends	(2,875)			(2,875)			(8,625)	(8,625)
Net income available to common equity	80,373			93,400			265,137	248,735
Common shareholder dividends	(31,806)			(30,149)			(95,417)	(90,647)
Unvested share-based payment awards	(190)			(194)			(588)	(609)
Undistributed earnings	48,377			63,057			169,132	157,479
Undistributed earnings allocated to common shareholders	48,090			62,648			168,136	156,454
Undistributed earnings allocated to unvested share-based payment awards	287			409			996	1,025
Basic
Distributed earnings to common shareholders	31,806			30,149			95,417	90,647
Undistributed earnings allocated to common shareholders	48,090			62,648			168,136	156,454
Total common shareholders earnings, basic	79,896			92,796			263,553	247,102
Diluted
Distributed earnings to common shareholders	31,806			30,149			95,417	90,647
Undistributed earnings allocated to common shareholders	48,090			62,648			168,136	156,454
Total common shareholders earnings, diluted	$ 79,896			$ 92,796			$ 263,553	$ 247,102
Weighted average common shares outstanding	150,035			149,321			149,929	149,063
Effect of dilutive common stock awards	980			942			1,042	1,141
Diluted weighted average common shares outstanding	151,014			150,262			150,971	150,205
Basic earnings per common share	$ 0.53			$ 0.62			$ 1.76	$ 1.66
Diluted earnings per common share	$ 0.53			$ 0.62			$ 1.75	$ 1.65