Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
OPERATING ACTIVITIES
Net income	$ 151,150	$ 173,152
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	35,933	36,660
Provision for credit losses	31,999	14,048
Loss on sale of investments	391	226
Net amortization (accretion) of investment securities and assets	10,647	(32,531)
Net amortization on borrowings	114	274
Stock-based compensation expense	9,617	11,475
Gain on sale of foreclosed assets and other real estate owned	(193)	(424)
Gain on sale of mortgage loans held for sale	(5,711)	(7,187)
Gain on sale of loans	0	(282)
Deferred income taxes	4,202	2,924
Income from bank owned life insurance	(9,811)	(8,189)
Loss from early retirement of TruPS	0	365
Originations of mortgage loans held for sale	(207,822)	(436,477)
Proceeds from sale of mortgage loans held for sale	205,329	467,261
Changes in assets and liabilities:
Interest receivable	(7,469)	(5,852)
Other assets	(99,325)	(18,712)
Accrued interest and other liabilities	5,115	34,850
Income taxes payable	(3,730)	(5,373)
Net cash provided by operating activities	120,436	226,208
INVESTING ACTIVITIES
Net change in loans	(709,735)	(1,344,441)
Proceeds from sale of loans	69,760	51,856
Net change in due from banks - time	695	592
Purchases of premises and equipment, net	(26,556)	(25,757)
Proceeds from sale of foreclosed assets and other real estate owned	1,867	3,476
Proceeds from maturities of available-for-sale securities	494,388	974,625
Purchases of available-for-sale securities	(2,286)	(261,375)
Proceeds from maturities of held-to-maturity securities	65,786	60,215
Purchases of held-to-maturity securities	(62,885)	(329,660)
Proceeds from bank owned life insurance death benefits	3,686	1,873
Purchase of Spirit of Texas Bancshares, Inc.	0	276,396
Net cash used in investing activities	(165,280)	(592,200)
FINANCING ACTIVITIES
Net change in deposits	(316,514)	63,128
Repayments of TruPS	0	(56,189)
Dividends paid on common stock	(75,926)	(69,963)
Net change in other borrowed funds	488,559	(411,250)
Net change in federal funds purchased and securities sold under agreements to repurchase	(85,921)	(16,890)
Net shares cancelled under stock compensation plans	(2,662)	(4,105)
Shares issued under employee stock purchase plan	833	1,151
Repurchases of common stock	(39,999)	(111,133)
Net cash used in financing activities	(31,630)	(605,251)
DECREASE IN CASH AND CASH EQUIVALENTS	(76,474)	(971,243)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	682,122	1,650,653
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 605,648	$ 679,410