CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net (loss) income	$ (73,351)	$ 77,245
Adjustments to net income:
Depreciation and amortization expense	5,525	4,636
Provision for credit losses	186,089	1,860
Share-based compensation expense	4,848	5,313
Loss (gain) on sales and disposals of premises and equipment	211	(170)
Loss (gain) on sale of or write down of other real estate owned	55	(75)
Net amortization on securities	3,739	2,573
Net (accretion) of discounts/premiums for acquired loans and deferred loan fees/costs	(9,652)	(12,271)
Gain on sales of investment securities available-for-sale	(7,739)	(639)
Originations of loans held for sale	(10,163)	(59,801)
Proceeds from the sales of and principal payments from loans held for sale	13,490	61,356
Loss (gain) on sales of loans	1,261	(2,631)
Deferred income tax (benefit) expense	(46,608)	1,988
Change in accrued expenses and other liabilities, net	70,342	(11,315)
Income from bank owned life insurance, net	(2,119)	(1,367)
Amortization of core deposit intangible	8,005	8,717
Change in accrued interest receivable and other assets, net	(46,110)	(462)
Net cash provided by operating activities	97,823	74,957
Cash flows from investing activities:
Net increase in interest-bearing time deposits with financial institutions	0	3,187
Proceeds from sale of other real estate owned	0	390
Loan originations and payments, net	(527,053)	46,104
Proceeds from loans held for sale previously classified as portfolio loans	38,246	74,070
Purchase of loans held for investment	(66,470)	(48,903)
Proceeds from prepayments and maturities of held-to-maturity securities	5,208	2,214
Purchase of securities available-for-sale	(458,667)	(400,409)
Proceeds from prepayments and maturities of securities available-for-sale	63,985	55,549
Proceeds from sale of securities available-for-sale	339,853	227,138
Proceeds from the sales of premises and equipment	42	11,108
Proceeds from bank owned insurance death benefit	0	405
Purchases of premises and equipment	(1,198)	(5,101)
Change in FHLB, FRB and other stock, at cost	(44)	2,416
Funding of CRA investments	(7,375)	(5,338)
Change in cash acquired in acquisitions, net	937,100	0
Net cash provided by (used in) investing activities	323,627	(37,170)
Cash flows from financing activities:
Net increase in deposit accounts	1,162,194	203,571
Net change in short-term borrowings	(681,000)	(86,075)
Repayment of long-term FHLB borrowings	(5,000)	(10,000)
Proceeds from issuance of subordinated debt, net	147,359	122,453
Cash dividends paid	(29,874)	(27,541)
Repurchase and retirement of common stock	0	(65,969)
Proceeds from exercise of stock options	1,024	381
Restricted stock surrendered and canceled	(1,273)	(2,629)
Net cash provided by financing activities	593,430	134,191
Net increase in cash and cash equivalents	1,014,880	171,978
Cash and cash equivalents, beginning of period	326,850	203,406
Cash and cash equivalents, end of period	1,341,730	375,384
Supplemental cash flow disclosures:
Interest paid	28,057	39,469
Income taxes paid	125	26,634
Noncash investing activities during the period:
Transfers from portfolio loans to loans held for sale	42,169	75,175
Transfers from loans to other real estate owned	0	203
Recognition of operating lease right-of-use assets	(11,118)	(48,685)
Recognition of operating lease liabilities	11,118	(48,685)
Receivable on unsettled security sales	6,529	0
Due on unsettled security purchases	(33,960)	0
Acquisitions (See Note 4):
Fair value of stock and equity award consideration	749,603	0
Cash consideration	2	0
Fair value of assets acquired	8,097,225	0
Liabilities assumed	$ 7,347,620	$ 0