Consolidated Statements of Cash Flows	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 172,225,000	$ 143,558,000
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	9,746,000	9,493,000
Provision for credit losses	(3,203,000)	27,550,000
Securities premium amortization, net	48,333,000	28,586,000
Discount accretion on purchased loans	(1,771,000)	(3,209,000)
Gain on sale of assets, net	(1,110,000)	(3,882,000)
Deferred federal income tax benefit	3,017,000	7,080,000
Change in loans held-for-sale	34,562,000	(69,987,000)
Change in other assets	6,308,000	(13,064,000)
Change in other liabilities	(2,237,000)	8,780,000
Total adjustments	93,645,000	(8,653,000)
Net cash provided by operating activities	265,870,000	134,905,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash received in acquisition of TB&T Bancshares, Inc.		61,028,000
Activity in available-for-sale securities:
Sales	10,631,000	263,042,000
Maturities	8,270,218,000	5,851,760,000
Purchases	(9,972,985,000)	(6,902,770,000)
Net increase in loans held-for-investment	(110,404,000)	(653,105,000)
Purchases of bank premises and equipment	(14,282,000)	(12,539,000)
Proceeds from sale of bank premises and equipment and other assets	785,000	1,192,000
Net cash used in investing activities	(1,816,037,000)	(1,391,392,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in noninterest-bearing deposits	591,708,000	647,454,000
Net increase in interest-bearing deposits	625,592,000	494,503,000
Net increase in borrowings	218,586,000	121,807,000
Common stock transactions:
Proceeds from stock option exercises	4,673,000	3,990,000
Dividends paid	(58,334,000)	(51,842,000)
Repurchase of stock		(8,008,000)
Net cash provided by financing activities	1,382,225,000	1,207,904,000
NET DECREASE IN CASH AND CASH EQUIVALENTS	(167,942,000)	(48,583,000)
CASH AND CASH EQUIVALENTS, beginning of period	729,084,000	282,604,000
Total cash and cash equivalents	561,142,000	234,021,000
SUPPLEMENTAL INFORMATION AND NONCASH TRANSACTIONS:
Interest paid	4,938,000	12,466,000
Federal income taxes paid	31,073,000	33,534,000
Transfer of loans and bank premises to other real estate	296,000	45,000
Investment securities purchased but not settled	$ 174,236,000	53,730,000
Stock issued in acquisition of TB&T Bancshares, Inc.		$ 220,273,000