Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net income	$ 294,969	$ 167,703
Adjustments reconciling net income to net cash provided by (used in) operating activities:
Depreciation	12,864	11,843
Net (gains) losses on sale or disposal of premises and equipment	3,200	(125)
Net write-downs on other assets	260	1,366
Provision for credit losses	(38,124)	146,890
Net write-downs and (gains) losses on sale of other real estate owned	(581)	715
Share-based compensation expense	5,884	2,708
Amortization of intangible assets	11,578	15,422
Amortization of operating lease right of use assets	12,389	12,408
Provision for deferred taxes	32,074	(28,652)
Net amortization of investment securities available-for-sale	2,534	4,702
Net amortization of investment securities held-to-maturity	14	0
Net gain on securities	(519)	(5)
Accretion of discount on purchased loans, net	(13,537)	(22,663)
Net amortization on other borrowings	330	152
Amortization of subordinated deferrable interest debentures	1,485	1,455
Loan servicing asset impairment (recovery)	(9,990)	30,566
Originations of mortgage loans held for sale	(6,231,286)	(6,492,434)
Payments received on mortgage loans held for sale	38,178	38,919
Proceeds from sales of mortgage loans held for sale	5,752,055	6,888,287
Net gains on mortgage loans held for sale	(126,533)	(270,503)
Originations of SBA loans	(51,155)	(104,160)
Proceeds from sales of SBA loans	54,861	99,369
Net gains on sale of SBA loans	(5,059)	(6,250)
Increase in cash surrender value of bank owned life insurance	(3,628)	(2,768)
Gain on bank owned life insurance proceeds	(603)	(948)
Net gains on other loans held for sale	(457)	0
Changes in FDIC loss-share payable, net of cash payments	0	223
Change attributable to other operating activities	1,244	(114,858)
Net cash provided by (used in) operating activities	(257,553)	379,362
Investing Activities, net of effects of business combinations
Proceeds from maturities of time deposits in other banks	249	0
Purchases of investment securities held-to-maturity	(64,517)	0
Proceeds from maturities and paydowns of securities available-for-sale	281,244	306,886
Proceeds from maturities and paydowns of securities held-to-maturity	52	0
Net decrease in other investments	1,102	18,095
Net increase in loans	(215,289)	(2,029,595)
Purchases of premises and equipment	(21,990)	(14,164)
Proceeds from sale of premises and equipment	993	421
Proceeds from sales of other real estate owned	10,141	7,777
Payments paid to FDIC under loss-share agreements	0	(389)
Purchases of bank owned life insurance	(100,000)	0
Proceeds from bank owned life insurance	1,309	3,381
Payments received on other loans held for sale	9,136	0
Proceeds from sales of other loans held for sale	156,803	0
Net cash and cash equivalents received from acquisitions	0	(2,417)
Net cash provided by (used in) investing activities	59,233	(1,710,005)
Financing Activities, net of effects of business combinations
Net increase in deposits	1,875,666	2,038,847
Net decrease in securities sold under agreements to repurchase	(7,139)	(11,532)
Proceeds from other borrowings	0	7,053,149
Repayment of other borrowings	(110)	(7,576,455)
Repayment of subordinated deferrable interest debentures	0	(5,155)
Proceeds from exercise of stock options	4,499	981
Dividends paid - common stock	(31,354)	(31,262)
Purchase of treasury shares	(8,108)	(7,988)
Net cash provided by financing activities	1,833,454	1,460,585
Net increase in cash and cash equivalents	1,635,134	129,942
Cash and cash equivalents at beginning of period	2,117,306	621,849
Cash and cash equivalents at end of period	3,752,440	751,791
Cash paid during the period for:
Interest	35,389	78,705
Income taxes	55,651	56,371
Loans transferred to other real estate owned	2,274	6,871
Loans transferred from loans held for sale to loans held for investment	134,941	135,689
Loans transferred from loans held for investment to loans held for sale	0	46,845
Loans provided for the sales of other real estate owned	1,052	592
Right-of-use assets obtained in exchange for new operating lease liabilities	10,270	11,040
Change in unrealized gain (loss) on securities available-for-sale, net of tax	(11,620)	19,109
Change in unrealized gain on cash flow hedge, net of tax	$ 0	$ 147