Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net income	$ 111,464,000	$ 142,797,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit loss	5,216,000	2,336,000
Specific reserve, other real estate owned	16,000	2,065,000
Depreciation of bank premises and equipment	10,930,000	13,235,000
(Gain) loss on sale of bank premises and equipment	(3,080,000)	15,000
(Gain) loss on sale of other real estate owned	(1,174,000)	519,000
Accretion of investment securities discounts	(732,000)	(279,000)
Amortization of investment securities premiums	8,773,000	22,329,000
Investment securities transactions, net		4,000
Unrealized loss on equity securities with readily determinable fair values	498,000	65,000
Proceeds from settlements of claims		2,870,000
Stock based compensation expense	229,000	273,000
Earnings from affiliates and other investments	(4,079,000)	(61,313,000)
Deferred income taxes	(589,000)	(821,000)
(Increase) decrease in accrued interest receivable	(137,000)	4,902,000
(Increase) decrease in other assets	(3,774,000)	12,097,000
Increase in other liabilities	43,821,000	24,904,000
Net cash provided by operating activities	167,382,000	165,998,000
Investing activities:
Proceeds from maturities of securities	2,075,000	1,200,000
Proceeds from sales and calls of available for sale securities	0	2,865,000
Purchases of available for sale securities	(818,988,000)	(2,129,883,000)
Principal collected on mortgage backed securities	415,801,000	1,009,379,000
Net decrease in loans	177,727,000	134,517,000
Purchases of other investments	(68,253,000)	(42,037,000)
Distributions from other investments	3,133,000	59,955,000
Purchases of bank premises and equipment	(8,571,000)	(4,259,000)
Proceeds from sales of bank premises and equipment	10,144,000	1,255,000
Proceeds from sales of other real estate owned	6,237,000	6,320,000
Net cash used in investing activities	(280,695,000)	(960,688,000)
Financing activities:
Net increase in non-interest bearing demand deposits	263,524,000	703,414,000
Net increase in savings and interest bearing demand deposits	70,287,000	461,049,000
Net decrease in time deposits	(8,436,000)	(9,554,000)
Net increase in securities sold under repurchase agreements	73,696,000	2,382,000
Net decrease in other borrowed funds	(96,000)	(94,000)
Purchase of treasury stock	(40,549,000)	(48,000)
Proceeds from stock transactions	387,000	1,996,000
Payments of cash dividends	(38,026,000)	(34,813,000)
Net cash provided by financing activities	320,787,000	1,124,332,000
Increase in cash and cash equivalents	207,474,000	329,642,000
Cash and cash equivalents at beginning of period	3,209,242,000	1,997,238,000
Cash and cash equivalents at end of period	3,416,716,000	2,326,880,000
Supplemental cash flow information:
Interest paid	12,701,000	13,991,000
Income taxes paid	3,643,000	16,130,000
Non-cash investing and financing activities:
Net transfers from loans to other real estate owned	1,277,000	$ 16,587,000
Net transfers from bank premises and equipment to other assets	$ 2,476,000