CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
OPERATING ACTIVITIES:
Net income	$ 50,927,000	$ 50,401,000
Adjustments to reconcile net income to net cash provided by operations:
Depreciation and net amortization	5,289,000	5,561,000
Securities premium amortization (discount accretion), net	3,698,000	9,346,000
Loan (discount accretion) premium amortization, net	187,000	(323,000)
Provision for (reversal of) credit losses	(114,000)	(339,000)
Stock compensation expense	1,838,000	1,666,000
Deferred tax expense (benefit)	(316,000)	643,000
Net (gain) loss on sale of AFS securities	5,601,000	3,720,000
Net (gain) loss on sale of equity securities	(5,058,000)	0
Loss on impairment of investments	0	38,000
Net loss on premises and equipment	88,000	433,000
Gross proceeds from sales of loans held for sale	9,025,000	15,835,000
Gross originations of loans held for sale	(10,024,000)	(14,966,000)
Net (gain) loss on OREO	(53,000)	(12,000)
Gain on purchase of subordinated notes	(587,000)	0
Net change in:
Interest receivable	1,085,000	(2,394,000)
Other assets	74,402,000	(3,472,000)
Interest payable	4,962,000	(346,000)
Other liabilities	(82,917,000)	62,242,000
Net cash provided by (used in) operating activities	58,033,000	128,033,000
Securities AFS:
Purchases	(717,315,000)	(523,339,000)
Sales	642,230,000	264,792,000
Maturities, calls and principal repayments	15,069,000	78,779,000
Securities HTM:
Maturities, calls and principal repayments	19,705,000	6,097,000
Proceeds from sales of equity securities	6,679,000	0
Proceeds from redemption of FHLB stock and equity investments	27,525,000	11,041,000
Purchases of FHLB stock and equity investments	(29,148,000)	(9,833,000)
Net loan paydowns (originations)	(182,187,000)	(317,731,000)
Purchases of premises and equipment	(3,195,000)	(4,965,000)
Proceeds from BOLI	951,000	0
Proceeds from sales of premises and equipment	370,000	7,000
Net proceeds from sales of OREO	146,000	34,000
Proceeds from sales of repossessed assets	102,000	47,000
Net cash provided by (used in) investing activities	(219,068,000)	(495,071,000)
FINANCING ACTIVITIES:
Net change in deposits	(80,402,000)	526,069,000
Net change in other borrowings	279,188,000	35,259,000
Proceeds from FHLB borrowings	1,328,000,000	1,050,000,000
Repayment of FHLB borrowings	(1,298,351,000)	(1,240,337,000)
Purchase of subordinated notes	(4,365,000)	0
Proceeds from stock option exercises	640,000	409,000
Cash paid to tax authority related to tax withholding on share-based awards	(227,000)	(352,000)
Purchase of common stock	(34,480,000)	(12,200,000)
Proceeds from the issuance of common stock for dividend reinvestment plan	601,000	635,000
Cash dividends paid	(21,708,000)	(21,909,000)
Net cash provided by (used in) financing activities	168,896,000	337,574,000
Net increase (decrease) in cash and cash equivalents	7,861,000	(29,464,000)
Cash and cash equivalents at beginning of period	199,252,000	201,753,000
Cash and cash equivalents at end of period	207,113,000	172,289,000
SUPPLEMENTAL DISCLOSURES FOR CASH FLOW INFORMATION:
Interest paid	55,493,000	11,334,000
Income taxes paid	8,000,000	5,200,000
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Loans transferred to other repossessed assets and real estate through foreclosure	61,000	197,000
Transfer of AFS to HTM securities	0	1,089,978,000
Unsettled trades to purchase securities	0	(174,038,000)
Unsettled trades to sell securities	$ 31,548,000	$ 72,001,000