Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities
Net income	$ 269,105	$ 346,540	$ 376,913
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	19,112	18,416	17,225
Net (gains) losses on sale or disposal of premises and equipment	(1,658)	156	2,882
Net write-downs on other assets	0	0	260
Provision for credit losses	142,656	71,697	(35,365)
Net write-downs and (gains) losses on sale of other real estate owned	(1,595)	(1,773)	538
Share-based compensation expense	9,950	6,706	7,948
Amortization of intangible assets	18,244	19,744	14,965
Amortization of operating lease right of use assets	11,363	12,639	15,739
Provision for deferred taxes	(20,468)	(35,677)	38,411
Net (accretion) amortization of debt securities available-for-sale	(5,616)	(644)	2,786
Net (accretion) amortization of debt securities held-to-maturity	(187)	37	40
Net amortization of other investments	1,091	722	62
Net loss (gain) on securities	304	(203)	(515)
Accretion of discount on purchased loans, net	(910)	285	(16,349)
Net amortization on other borrowings	843	433	438
Amortization of subordinated deferrable interest debentures	1,993	1,994	1,983
Loan servicing asset impairment (recovery)	0	(21,824)	(14,530)
Originations of mortgage loans held for sale	(3,620,664)	(3,949,676)	(7,780,436)
Payments received on mortgage loans held for sale	15,269	23,324	53,313
Proceeds from sales of mortgage loans held for sale	3,695,259	4,493,742	7,459,163
Net (gains) losses on mortgage loans held for sale	2,072	93,133	(152,422)
Originations of SBA loans	(27,410)	(46,479)	(67,865)
Proceeds from sales of SBA loans	30,462	57,171	71,610
Net gains on sales of SBA loans	(1,557)	(5,552)	(6,623)
Increase in cash surrender value of bank owned life insurance	(8,777)	(7,305)	(5,385)
Gain on bank owned life insurance proceeds	(486)	(55)	(603)
Gains on sale of other loans held for sale	0	0	(457)
Gain on sale of mortgage servicing rights	0	(1,356)	0
Gain on debt redemption	(1,148)	0	0
(Increase) decrease in interest receivable	(9,662)	(20,125)	19,337
Increase (decrease) in interest payable	26,946	6,217	(1,175)
Increase (decrease) in taxes payable	2,271	5,177	7,005
Change attributable to other operating activities	22,157	(4,991)	247
Net cash provided by operating activities	568,959	1,062,473	9,140
Investing Activities, net of effects of business combinations
Proceeds from maturities of time deposits in other banks	0	0	249
Purchases of securities available-for-sale	(30,548)	(1,172,323)	0
Purchases of securities held-to-maturity	(8,543)	(57,408)	(80,355)
Proceeds from prepayments and maturities of securities available-for-sale	142,082	186,849	364,907
Proceeds from prepayments and maturities of securities held-to-maturity	2,082	2,357	465
Proceeds from sale of securities available-for-sale	5,141	0	0
Net (increase) decrease in other investments	38,112	(63,959)	(18,897)
Net increase in loans	(485,459)	(3,345,287)	(566,237)
Payments received on other loans held for sale	0	0	9,136
Purchase of loan pool	0	(472,266)	0
Proceeds from sale of mortgage servicing rights	0	119,845	0
Purchases of premises and equipment	(17,531)	(13,568)	(25,448)
Proceeds from sale of premises and equipment	3,925	46	1,958
Proceeds from sales of other real estate owned	10,655	5,086	11,790
Purchase of bank owned life insurance	0	(50,000)	(150,000)
Proceeds from bank owned life insurance	1,890	101	1,309
Proceeds from sales of other loans held for sale	0	0	156,803
Net cash proceeds paid in acquisitions	0	(14,003)	(126,664)
Net cash used in investing activities	(338,194)	(4,874,530)	(420,984)
Financing Activities, net of effects of business combinations
Net increase (decrease) in deposits	1,245,771	(202,815)	2,708,021
Net decrease in securities sold under agreements to repurchase	0	(5,845)	(5,796)
Proceeds from other borrowings	15,842,000	3,950,000	0
Repayment of other borrowings	(17,207,845)	(2,814,576)	(296,325)
Proceeds from exercise of stock options	476	2,799	4,532
Dividends paid - common stock	(41,649)	(41,610)	(41,798)
Purchase of treasury shares	(20,346)	(22,421)	(9,439)
Net cash provided by (used in) financing activities	(181,593)	865,532	2,359,195
Net increase (decrease) in cash, cash equivalents and restricted cash	49,172	(2,946,525)	1,947,351
Cash, cash equivalents and restricted cash at beginning of period	1,118,132	4,064,657	2,117,306
Cash, cash equivalents and restricted cash at end of period	1,167,304	1,118,132	4,064,657
Cash paid during the year for:
Interest	418,445	86,643	48,960
Income taxes	101,328	133,894	71,807
Loans transferred to other real estate owned	14,416	346	4,258
Loans transferred from loans held for sale to loans held for investment	0	196,891	170,435
Loans provided for the sales of other real estate owned	0	2,288	1,052
Right-of-use assets obtained in exchange for new operating lease liabilities	2,827	7,226	12,792
Assets acquired in business combination	0	3,216	886,553
Liabilities assumed in business combination	0	(10,787)	690,116
Change in unrealized gain (loss) on securities available-for-sale, net of tax	$ 10,568	$ (62,097)	$ (17,915)