CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
OPERATING ACTIVITIES:
Net income	$ 183,624	$ 195,378	$ 201,048
Adjustments to reconcile net income to net cash provided from operating activities:
Depreciation	17,873	16,933	17,345
Deferred income and expense, net of amortization	(4,194)	(3,757)	(38,786)
Capitalized loan servicing rights, net of amortization	1,830	1,326	(1,805)
Amortization of core deposit intangibles	3,756	5,279	6,571
Loss (gain) on sale of securities, net	19,242	3,248	(482)
Net change in valuation of financial instruments carried at fair value	4,218	(807)	(4,616)
Gain on sale of branches, including related deposits	0	(7,804)
Decrease in deferred taxes	1,514	7,624	16,357
(Decrease) increase in current taxes payable	(3,170)	8,250	(3,643)
Stock-based compensation	9,169	8,870	9,258
Net change in cash surrender value of BOLI	(8,742)	(7,100)	(4,685)
Gain on sale of loans, excluding capitalized servicing rights	(6,151)	(4,556)	(26,140)
(Gain) loss on disposal of real estate held for sale and property and equipment, net	(352)	102	(2,305)
Financing Receivable, Credit Loss, Expense (Reversal)	10,789	10,364	(33,388)
Gain (Loss) on Extinguishment of Debt	0	765	2,284
Origination of loans held for sale	(242,844)	(406,915)	(1,102,663)
Proceeds from sales of loans held for sale	266,540	415,635	1,276,111
Net change in:
Other assets	(8,968)	(39,028)	2,200
Other liabilities	13,065	34,244	(11,083)
Net cash provided from operating activities	257,199	238,051	301,578
INVESTING ACTIVITIES:
Purchases of securities—available-for-sale	(58,173)	(659,905)	(2,805,251)
Principal repayments and maturities of securities—available-for-sale	173,055	368,996	1,314,484
Proceeds from sales of securities—available-for-sale	368,945	214,335	83,663
Purchases of securities—held-to-maturity	0	(190,645)	(135,615)
Principal repayments and maturities of securities—held-to-maturity	58,406	56,056	32,487
Purchases of equity securities	0	0	(4,750)
Proceeds from sales of equity securities	0	0	4,796
Loan (originations) repayments, net	(643,959)	(897,505)	795,892
Purchases of loans and participating interest in loans	0	(126,556)	(5,086)
Proceeds from sales of other loans	14,038	14,034	46,028
Net cash paid related to branch divestiture	0	(168,137)
Purchases of property and equipment	(14,651)	(14,724)	(10,493)
Proceeds from sale of real estate held for sale and sale of other property	4,669	6,088	11,759
Proceeds from FHLB stock repurchase program	153,397	15,080	4,358
Purchase of FHLB stock	(165,425)	(15,080)	0
Proceeds from Securities Purchased under Agreements to Resell	300,000	0	0
Purchase of securities purchased under agreements to resell	0	0	(300,000)
Investment in bank-owned life insurance	(66)	(50,053)	(50,053)
Other	1,693	3,459	2,355
Net cash provided from (used by) investing activities	191,929	(1,444,557)	(1,015,426)
FINANCING ACTIVITIES:
(Decrease) increase in deposits, net	(590,562)	(528,672)	1,759,638
Repayment of long term FHLB borrowing	0	(50,000)	(100,000)
Advances of overnight and short-term FHLB borrowings, net	273,000	50,000	0
Proceeds from (Payments for) Other Financing Activities	(49,923)	(31,690)	79,704
Repayment of junior subordinated debentures	0	(50,518)	(8,248)
Proceeds from redemption of trust preferred securities related to junior subordinated debentures	0	1,518	248
Cash dividends paid	(66,765)	(61,078)	(57,621)
Cash paid for repurchase of common stock	0	(10,960)	(56,528)
Taxes paid related to net share settlement of equity awards	(3,476)	(3,332)	(3,228)
Net cash (used by) provided from financing activities	(437,726)	(684,732)	1,613,965
NET CHANGE IN CASH AND CASH EQUIVALENTS	11,402	(1,891,238)	900,117
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	243,062	2,134,300	1,234,183
CASH AND CASH EQUIVALENTS, END OF YEAR	254,464	243,062	2,134,300
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid in cash	110,845	18,583	24,278
Taxes paid	38,671	24,885	29,017
NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Transfer of loans to real estate owned and other repossessed assets	1,185	0	512
Dividends accrued but not paid until after period end	1,084	1,158	1,338
Transfer of Loans Held-for-sale to Portfolio Loans	27,929	35,466	0
Debt Securities, Held-for-Trading, Transfer to Available-for-Sale	25,298	0	0
Securities, available-for-sale, transferred to held-to-maturity	0	462,159	0
DISPOSITIONS:
Assets divested	0	(1,539)	0
Liabilities divested	$ 0	$ (178,209)	$ 0