Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities
Net income	$ 124,962	$ 19,322
Adjustments reconciling net income to net cash provided by (used in) operating activities:
Depreciation	4,080	3,916
Net losses on sale or disposal of premises and equipment	139	125
Net write-downs on other assets	122	417
Provision for credit losses	(28,591)	41,047
Net write-downs and (gains) losses on sale of other real estate owned	(560)	885
Share-based compensation expense	1,753	559
Amortization of intangible assets	4,126	5,631
Amortization of operating lease right of use assets	2,979	3,400
Provision for deferred taxes	12,919	(7,333)
Net amortization of investment securities available for sale	1,121	1,385
Net loss on securities	12	9
Accretion of discount on purchased loans, net	(6,127)	(6,320)
Net amortization on other borrowings	112	46
Amortization of subordinated deferrable interest debentures	488	485
Loan servicing asset impairment (recovery)	(10,639)	22,165
Originations of mortgage loans held for sale	(2,340,847)	(1,252,379)
Payments received on mortgage loans held for sale	10,680	14,957
Proceeds from sales of mortgage loans held for sale	1,816,503	1,530,122
Net gains on mortgage loans held for sale	(41,720)	(40,809)
Originations of SBA loans	(11,976)	(11,647)
Proceeds from sales of SBA loans	12,518	20,062
Net gains on sale of SBA loans	(1,192)	(1,824)
Increase in cash surrender value of bank owned life insurance	(814)	(969)
Gain on bank owned life insurance proceeds	(603)	0
Net gains on other loans held for sale	(457)	0
Changes in FDIC loss-share payable, net of cash payments	0	(1,506)
Change attributable to other operating activities	(13,597)	(40,757)
Net cash provided by (used in) operating activities	(464,609)	300,989
Investing Activities, net of effects of business combinations
Proceeds from prepayments and maturities of securities available for sale	112,730	76,386
Net (increase) decrease in other investments	570	(14,844)
Net increase in loans	(72,093)	(264,063)
Purchases of premises and equipment	(13,809)	(3,572)
Proceeds from sale of premises and equipment	930	0
Proceeds from sales of other real estate owned	4,048	1,284
Payments paid to FDIC under loss-share agreements	0	(25)
Proceeds from bank owned life insurance	1,309	0
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
Net cash provided by (used in) investing activities	199,624	(204,832)
Financing Activities, net of effects of business combinations
Net increase (decrease) in deposits	918,050	(182,455)
Net decrease in securities sold under agreements to repurchase	(2,321)	(5,475)
Proceeds from other borrowings	0	2,770,000
Repayment of other borrowings	(36)	(2,625,084)
Repayment of subordinated deferrable interest debentures	0	(5,155)
Proceeds from exercise of stock options	3,002	701
Dividends paid - common stock	(10,432)	(10,426)
Purchase of treasury shares	(1,456)	(7,956)
Net cash provided by (used in) financing activities	906,807	(65,850)
Net increase in cash and cash equivalents	641,822	30,307
Cash and cash equivalents at beginning of period	2,117,306	621,849
Cash and cash equivalents at end of period	2,759,128	652,156
Cash paid (received) during the period for:
Interest	11,335	35,234
Income taxes	(1)	(77)
Loans transferred to other real estate owned	449	3,674
Loans transferred from loans held for sale to loans held for investment	48,313	0
Loans provided for the sales of other real estate owned	0	299
Right-of-use assets obtained in exchange for new operating lease liabilities	0	2,889
Change in unrealized gain (loss) on securities available for sale, net of tax	(7,415)	21,653
Change in unrealized gain (loss) on cash flow hedge, net of tax	$ 0	$ (97)