Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net income	$ 376,913	$ 261,988	$ 161,441
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	17,225	15,759	13,120
Net losses on sale or disposal of premises and equipment	2,882	777	41
Net write-downs on other assets	260	1,715	6,210
Provision for credit losses	(35,365)	145,380	19,758
Net write-downs and losses on sale of other real estate owned	538	1,049	496
Share-based compensation expense	7,948	3,810	3,424
Amortization of intangible assets	14,965	19,612	17,713
Amortization of operating lease right of use assets	15,739	19,740	10,264
Provision for deferred taxes	38,411	(7,929)	22,821
Net amortization of debt securities available-for-sale	2,786	6,153	4,680
Net amortization of debt securities held-to-maturity	40	0	0
Net amortization of other investments	62	0	0
Net gain on securities	(515)	(5)	(138)
Accretion of discount on purchased loans, net	(16,349)	(27,351)	(18,978)
Net amortization on other borrowings	438	256	80
Amortization of subordinated deferrable interest debentures	1,983	1,940	1,655
Loan servicing asset impairment (recovery)	(14,530)	40,067	508
Originations of mortgage loans held for sale	(7,780,436)	(9,067,706)	(3,791,311)
Payments received on mortgage loans held for sale	53,313	43,663	17,445
Proceeds from sales of mortgage loans held for sale	7,459,163	9,864,464	2,620,290
Net gains on mortgage loans held for sale	(152,422)	(387,124)	(74,546)
Originations of SBA loans	(67,865)	(97,017)	(41,435)
Proceeds from sales of SBA loans	71,610	109,296	65,862
Net gains on sales of SBA loans	(6,623)	(7,226)	(6,058)
Increase in cash surrender value of bank owned life insurance	(5,385)	(3,630)	(2,692)
Gain on bank owned life insurance proceeds	(603)	(948)	(3,583)
Gains on sale of other loans held for sale	(457)	0	0
Loss on sale of loans	0	386	1,233
Changes in FDIC loss-share receivable/payable, net of cash payments received	0	997	3,865
(Increase) decrease in interest receivable	19,337	(23,892)	(15,392)
Increase (decrease) in interest payable	(1,175)	(6,036)	5,855
Increase (decrease) in taxes payable	7,005	(12,062)	(3,597)
Change attributable to other operating activities	247	(97,730)	40,758
Net cash provided by (used in) operating activities	9,140	798,396	(940,211)
Investing Activities, net of effects of business combinations
Proceeds from maturities of time deposits in other banks	249	0	10,563
Purchases of securities available-for-sale	0	0	(219,352)
Purchases of securities held-to-maturity	(80,355)	0	0
Proceeds from prepayments and maturities of securities available-for-sale	364,907	435,204	266,171
Proceeds from prepayments and maturities of securities held-to-maturity	465	0	0
Proceeds from sale of securities available-for-sale	0	0	64,995
Net decrease (increase) in other investments	(18,897)	37,222	(44,935)
Net increase in loans	(566,237)	(1,733,057)	(870,132)
Payments received on other loans held for sale	9,136	12,954	0
Purchase of acquired formerly serviced portfolio	0	0	(103,530)
Purchases of premises and equipment	(25,448)	(18,116)	(11,581)
Proceeds from sale of premises and equipment	1,958	718	5,587
Proceeds from sales of other real estate owned	11,790	14,059	10,140
Purchase of bank owned life insurance	(150,000)	0	0
Payments paid to FDIC under loss-sharing agreements	0	(20,639)	(3,710)
Proceeds from bank owned life insurance	1,309	3,381	7,429
Proceeds from sales of other loans held for sale	156,803	0	0
Proceeds from sales of loans	0	69,965	157,087
Net cash proceeds received from (paid in) acquisitions	(126,664)	(2,417)	244,181
Net cash used in investing activities	(420,984)	(1,200,726)	(487,087)
Financing Activities, net of effects of business combinations
Net increase in deposits	2,708,021	2,932,864	334,437
Net decrease in securities sold under agreements to repurchase	(5,796)	(8,994)	(22,094)
Proceeds from other borrowings	0	7,202,981	5,236,572
Repayment of other borrowings	(296,325)	(8,176,491)	(4,141,349)
Repayment of subordinated deferrable interest debentures	0	(5,155)	0
Proceeds from exercise of stock options	4,532	2,262	5,139
Dividends paid - common stock	(41,798)	(41,685)	(24,675)
Purchase of treasury shares	(9,439)	(7,995)	(18,410)
Net cash provided by financing activities	2,359,195	1,897,787	1,369,620
Net increase (decrease) in cash, cash equivalents and restricted cash	1,947,351	1,495,457	(57,678)
Cash, cash equivalents and restricted cash at beginning of period	2,117,306	621,849	679,527
Cash, cash equivalents and restricted cash at end of period	4,064,657	2,117,306	621,849
Cash paid during the year for:
Interest	48,960	94,786	125,373
Income taxes	71,807	98,609	35,865
Loans transferred to other real estate owned	4,258	7,398	6,229
Loans transferred from loans held for sale to loans held for investment	170,435	196,804	0
Loans transferred from loans held for investment to loans held for sale	0	179,407	8,293
Loans provided for the sales of other real estate owned	1,052	767	144
Initial recognition of operating lease right-of-use assets	0	0	27,286
Initial recognition of operating lease liabilities	0	0	29,651
Right-of-use assets obtained in exchange for new operating lease liabilities	12,792	54,107	6,016
Assets acquired in business combination	886,553	0	5,194,955
Liabilities assumed in business combination	690,116	0	4,325,642
Issuance of common stock in acquisition	0	0	869,294
Change in unrealized gain (loss) on securities available-for-sale, net of tax	(17,915)	15,363	23,320
Change in unrealized gain on cash flow hedge, net of tax	$ 0	$ 147	$ (498)