Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net income (loss)	$ 167,703	$ 100,193
Adjustments reconciling net income to net cash provided by (used in) operating activities:
Depreciation	11,843	9,077
Net (gains) losses on sale or disposal of premises and equipment including write-downs	(125)	159
Net write-downs on other assets	1,366	4,359
Provision for credit losses	146,890	14,065
Net losses on sale of other real estate owned including write-downs	715	158
Share-based compensation expense	2,708	2,450
Amortization of intangible assets	15,422	11,972
Amortization of operating lease right-of-use assets	12,408	7,145
Provision for deferred taxes	(28,652)	12,084
Net amortization of investment securities available for sale	4,702	3,069
Net gain on securities	(5)	(139)
Accretion of discount on purchased loans, net	(22,663)	(9,526)
Accretion on other borrowings	152	33
Accretion on subordinated deferrable interest debentures	1,455	1,170
Loan servicing asset impairment	30,566	141
Originations of mortgage loans held for sale	(6,492,434)	(2,376,070)
Payments received on mortgage loans held for sale	38,919	4,438
Proceeds from sales of mortgage loans held for sale	6,888,287	1,660,599
Net gains on sale of mortgage loans held for sale	(270,503)	(52,605)
Originations of SBA loans	(104,160)	(22,121)
Proceeds from sales of SBA loans	99,369	42,647
Net gains on sale of SBA loans	(6,250)	(4,220)
Increase in cash surrender value of bank owned life insurance	(2,768)	(1,861)
Gain on bank owned life insurance proceeds	(948)	(4,335)
Loss on sale of loans	0	1,954
Changes in FDIC loss-share payable, net of cash payments	223	3,695
Change attributable to other operating activities	(114,858)	4,166
Net cash provided by (used in) operating activities	379,362	(587,303)
Investing Activities, net of effects of business combinations
Proceeds from maturities of time deposits in other banks	0	10,313
Purchases of securities available for sale	0	(219,352)
Proceeds from prepayments and maturities of securities available for sale	306,886	176,760
Proceeds from sales of securities available for sale	0	64,995
Net (increase) decrease in other investments	18,095	(44,936)
Net increase in loans	(2,029,595)	(919,493)
Purchases of premises and equipment	(14,164)	(5,924)
Proceeds from sales of premises and equipment	421	5,330
Proceeds from sales of other real estate owned	7,777	7,448
Payments paid to FDIC under loss-share agreements	(389)	(3,692)
Proceeds from bank owned life insurance	3,381	8,178
Proceeds from sales of loans	0	96,162
Net cash and cash equivalents received in acquisitions	(2,417)	244,181
Net cash used in investing activities	(1,710,005)	(580,030)
Financing Activities, net of effects of business combinations
Net increase (decrease) in deposits	2,038,847	(33,042)
Net decrease in securities sold under agreements to repurchase	(11,532)	(24,985)
Proceeds from other borrowings	7,053,149	2,969,000
Repayment of other borrowings	(7,576,455)	(1,921,267)
Repayment of subordinated deferrable interest debentures	(5,155)	0
Proceeds from exercise of stock options	981	3,587
Dividends paid - common stock	(31,262)	(14,237)
Purchase of treasury shares	(7,988)	(11,561)
Net cash provided by financing activities	1,460,585	967,495
Net increase (decrease) in cash and cash equivalents	129,942	(199,838)
Cash and cash equivalents at beginning of period	621,849	679,527
Cash and cash equivalents at end of period	751,791	479,689
Cash paid (received) during the period for:
Interest	78,705	87,066
Income taxes	56,371	32,096
Loans transferred to other real estate owned	6,871	4,411
Loans transferred from loans held for sale to loans held for investment	135,689	0
Loans transferred from loans held for investment to loans held for sale	46,845	1,554
Loans provided for the sales of other real estate owned	592	144
Initial recognition of operating lease right-of-use assets	0	27,286
Initial recognition of operating lease liabilities	0	29,651
Right-of-use assets obtained in exchange for new operating lease liabilities	11,040	262
Assets acquired in business acquisitions	0	5,186,974
Liabilities assumed in business acquisitions	0	4,317,661
Change in unrealized gain (loss) on securities available for sale, net of tax	19,109	20,778
Change in unrealized gain (loss) on cash flow hedge, net of tax	$ 147	$ (470)