Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities:
Net income	$ 194,820,000	$ 197,396,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit loss	13,741,000	5,137,000
Specific reserve, other real estate owned	416,000	2,065,000
Depreciation of bank premises and equipment	16,355,000	19,263,000
(Gain) loss on sale of bank premises and equipment	(3,426,000)	5,000
(Gain) loss on sale of other real estate owned	(1,781,000)	160,000
Accretion of investment securities discounts	(1,257,000)	(400,000)
Amortization of investment securities premiums	11,617,000	29,749,000
Investment securities transactions, net		16,000
Unrealized loss on equity securities with readily determinable fair values	728,000	70,000
Proceeds from settlements of claims		2,870,000
Stock based compensation expense	347,000	391,000
Earnings from affiliates and other investments	(9,960,000)	(66,746,000)
Deferred income taxes	(1,838,000)	(792,000)
(Increase) decrease in accrued interest receivable	(6,483,000)	6,487,000
(Increase) decrease in other assets	(7,325,000)	7,436,000
Increase in other liabilities	82,553,000	21,381,000
Net cash provided by operating activities	288,507,000	224,488,000
Investing activities:
Proceeds from maturities of securities	2,200,000	1,200,000
Proceeds from sales and calls of available for sale securities	800,000	5,890,000
Purchases of available for sale securities	(1,160,632,000)	(2,856,135,000)
Principal collected on mortgage backed securities	605,706,000	1,333,256,000
Net decrease in loans	153,278,000	116,355,000
Purchases of other investments	(72,799,000)	(45,184,000)
Distributions from other investments	5,995,000	60,207,000
Purchases of bank premises and equipment	(12,798,000)	(6,070,000)
Proceeds from sales of bank premises and equipment	12,523,000	1,278,000
Proceeds from sales of other real estate owned	8,427,000	7,925,000
Net cash used in investing activities	(457,300,000)	(1,381,278,000)
Financing activities:
Net increase in non-interest bearing demand deposits	162,603,000	880,951,000
Net increase in savings and interest bearing demand deposits	158,665,000	608,052,000
Net (decrease) increase in time deposits	(58,630,000)	33,110,000
Net increase (decrease) in securities sold under repurchase agreements	67,471,000	(3,751,000)
Net decrease in other borrowed funds	(145,000)	(141,000)
Purchase of treasury stock	(51,939,000)	(704,000)
Proceeds from stock transactions	732,000	2,232,000
Payments of cash dividends	(75,375,000)	(72,839,000)
Net cash provided by financing activities	203,382,000	1,446,910,000
Increase in cash and cash equivalents	34,589,000	290,120,000
Cash and cash equivalents at beginning of period	3,209,242,000	1,997,238,000
Cash and cash equivalents at end of period	3,243,831,000	2,287,358,000
Supplemental cash flow information:
Interest paid	21,604,000	21,127,000
Income taxes paid	1,980,000	47,392,000
Non-cash investing and financing activities:
Net transfers from loans to other real estate owned	204,000	$ 16,370,000
Net transfers from bank premises and equipment to other assets	$ 2,476,000