Parent Company Only Financial Information, Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities
Net income	$ 182,956	$ 366,122	$ 350,994
Adjustments to reconcile net income to net cash provided by operating activities:
Net change in other assets and other liabilities	(14,556)	(6,539)	66,201
Net cash provided by operating activities	442,740	846,566	529,551
Cash flows from investing activities
Net cash (used in) investing activities	(1,436,257)	(5,254,811)	(1,584,186)
Cash flows from financing activities
Proceeds from (Repayments of) Short-Term Debt	(279,157)	251,674	101,946
Redemption of Corporation's senior notes	0	0	300,000
Proceeds from issuance of common stock for stock-based compensation plans	4,297	11,061	25,702
Purchase of treasury stock, open market purchases	0	(938)	0
Cash dividends on common stock	(129,534)	(123,137)	(116,061)
Cash dividends on preferred stock	(11,500)	(11,500)	(17,111)
Other		(938)
Net cash used in financing activities	1,295,885	4,004,185	1,364,102
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	302,368	(404,060)	309,467
Treasury Stock
Cash flows from financing activities
Other	0	(938)	0
Performance/Service Based RSAs, RSA, [Member]
Cash flows from financing activities
Payments for Repurchase of Common Stock	(6,593)	(6,480)	(4,847)
Parent Company Only
Cash Flows from Operating Activities
Net income	182,956	366,122	350,994
Adjustments to reconcile net income to net cash provided by operating activities:
(Increase) decrease in equity in undistributed net income (loss) of subsidiaries	107,441	(343,582)	28,802
Net change in other assets and other liabilities	(35,863)	14,159	17,102
Net cash provided by operating activities	254,534	36,699	396,898
Cash flows from investing activities
Net (increase) decrease in notes receivable from subsidiaries	(385,000)	115,000	20,000
Net cash (used in) investing activities	(385,000)	115,000	20,000
Cash flows from financing activities
Proceeds from (Repayments of) Short-Term Debt	(20,798)	(13,932)	(24,616)
Proceeds from issuance of long-term funding	292,740	0	0
Proceeds from issuance of common stock for stock-based compensation plans	4,297	11,061	25,702
Redemption of preferred stock	0	0	(164,458)
Purchase of treasury stock, open market purchases	0	0	(132,955)
Cash dividends on common stock	(129,534)	(123,137)	(116,061)
Cash dividends on preferred stock	(11,500)	(11,500)	(17,111)
Net cash used in financing activities	128,612	(144,928)	(434,346)
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	(1,854)	6,771	(17,448)
Cash and cash equivalents at end of year	42,901	44,755	37,984
Cash and cash equivalents at beginning of year	$ 44,755	$ 37,984	$ 55,432