Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 116,466,000	$ 113,297,000
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	6,436,000	6,407,000
Provision for Credit losses	10,132,000	(3,203,000)
Securities premium amortization, net	38,727,000	30,288,000
Discount accretion on purchased loans	(746,000)	(1,181,000)
Gain on sale of securities and other assets, net	(2,777,000)	(1,088,000)
Deferred federal income tax benefit	1,421,000	814,000
Change in loans held-for-sale	10,980,000	20,899,000
Change in other assets	(1,077,000)	(4,125,000)
Change in other liabilities	(21,216,000)	(13,792,000)
Total adjustments	41,880,000	35,019,000
Net cash provided by operating activities	158,346,000	148,316,000
Activity in available-for-sale securities:
Sales	188,363,000	10,631,000
Maturities	2,615,256,000	8,037,370,000
Purchases	(3,115,482,000)	(9,130,287,000)
Net increase in loans held-for-investment	(487,862,000)	(130,765,000)
Purchases of bank premises and equipment	(5,245,000)	(11,640,000)
Proceeds from sale of bank premises and equipment and other assets	6,000	494,000
Net cash used in investing activities	(804,964,000)	(1,224,197,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in noninterest-bearing deposits	323,804,000	444,341,000
Net increase in interest-bearing deposits	232,691,000	661,536,000
Net increase in borrowings	97,212,000	119,876,000
Common stock transactions:
Proceeds from stock option exercises	4,346,000	2,618,000
Dividends paid	(67,054,000)	(36,982,000)
Repuchase of stock	(7,405,000)	0
Net cash provided by financing activities	583,594,000	1,191,389,000
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(63,024,000)	115,508,000
CASH AND CASH EQUIVALENTS, beginning of period	528,588,000	729,084,000
CASH AND CASH EQUIVALENTS, end of period	465,564,000	844,592,000
SUPPLEMENTAL INFORMATION AND NONCASH TRANSACTIONS:
Interest paid	4,567,000	3,500,000
Federal income taxes paid	20,981,000	19,263,000
Transfer of loans to other real estate	0	283,000
Investment securities purchased but not settled	0	189,838,000
Restricted stock grant (forfeiture)	$ 1,210,000	$ (663,000)