CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 339,889	$ 60,351	$ 159,718
Adjustments to net income:
Depreciation and amortization expense	15,977	13,349	9,815
Provision for credit losses	(70,876)	191,816	5,719
Share-based compensation expense	13,264	10,859	10,528
Loss (gain) on sale and disposal of premises and equipment	234	255	(42)
Loss (gain) on sale of or write down of other real estate owned	0	112	(55)
Net amortization on securities	24,468	15,971	4,745
Net (accretion) of discounts/premiums for acquired loans and deferred loan fees/costs	(41,162)	(40,291)	(27,378)
Gain on sale of investment securities available-for-sale	(16,906)	(13,882)	(8,571)
Loss on debt extinguishment	180	0	0
Originations of loans held for sale	(51,098)	(14,251)	(98,232)
Proceeds from the sales of and principal payments from loans held for sale	44,734	16,552	111,952
Gain on sales of loans	(4,428)	(8,609)	(6,642)
Deferred income tax expense (benefit)	28,807	(42,622)	7,496
Change in accrued expenses and other liabilities, net	(29,038)	(9,455)	(6,265)
Income from bank-owned life insurance, net	(9,000)	(5,538)	(2,689)
Amortization of intangible assets	15,936	17,072	17,245
Change in accrued interest receivable and other assets, net	59,234	20,609	5,346
Net cash provided by operating activities	320,215	212,298	182,690
Cash flows from investing activities:
Net decrease in interest-bearing time deposits with financial institutions	629	0	3,435
Proceeds from sales of other real estate owned	0	534	405
Loan originations and payments, net	(1,022,505)	53,972	266,632
Proceeds from sales of loans previously classified as loans held for investment	1,530	1,338,325	86,313
Purchase of loans held for investment	0	(66,470)	(222,701)
Purchase of securities held-to-maturity	(48,695)	0	0
Proceeds from prepayments and maturities of securities held-to-maturity	10,334	13,959	7,318
Purchase of securities available-for-sale	(2,231,699)	(2,715,499)	(889,516)
Proceeds from prepayments and maturities of securities available-for-sale	563,061	268,463	114,520
Proceeds from sales of securities available-for-sale	901,137	766,512	551,784
Proceeds from the sales of premises and equipment	55	42	14,751
Proceeds from surrender of bank-owned life insurance	1,809	17,799	405
Purchase of bank-owned life insurance	(150,000)	0	0
Purchases of premises and equipment	(9,290)	(11,408)	(18,834)
Change in FHLB, FRB, and other stock, at cost	(62)	(22,664)	2,306
Funding of CRA investments, net	(24,001)	(10,182)	(15,069)
Change in cash acquired in acquisitions, net	0	937,100	0
Net cash (used in) provided by investing activities	(2,007,697)	570,483	(98,251)
Cash flows from financing activities:
Net increase in deposit accounts	901,412	399,678	240,158
Net change in short-term borrowings	548,000	(691,000)	(115,075)
Repayment of long-term FHLB borrowings	(21,503)	(5,000)	(35,500)
Redemption of subordinated debentures	(171,153)	0	(18,558)
Proceeds from issuance of subordinated debt, net	0	147,359	122,453
Cash dividends paid	(121,887)	(79,901)	(53,867)
Repurchase and retirement of common stock	(18,067)	0	(100,000)
Proceeds from exercise of stock options	1,001	1,652	2,679
Restricted stock surrendered and canceled	(6,384)	(1,653)	(3,285)
Net cash provided by (used in) financing activities	1,111,419	(228,865)	39,005
Net change in cash and cash equivalents	(576,063)	553,916	123,444
Cash and cash equivalents, beginning of year	880,766	326,850	203,406
Cash and cash equivalents, end of year	304,703	880,766	326,850
Supplemental cash flow disclosures:
Interest paid	38,761	57,020	79,386
Income taxes paid	86,535	36,158	52,093
Noncash investing activities during the period:
Transfers from portfolio loans to loans held for sale	1,006	1,330,946	89,259
Transfers from loans to other real estate owned	0	208	644
Transfers of investment securities from available-for-sale to held-to-maturity	319,924	0	0
Recognition of operating lease right-of-use assets	(5,003)	(12,277)	(52,701)
Recognition of operating lease liabilities	5,003	12,277	52,701
Assets acquired and liabilities assumed in acquisitions (See Note 25):
Fair value of stock and equity award consideration	0	749,603	0
Cash consideration	0	2	0
Fair value of assets acquired	0	8,102,281	0
Liabilities assumed	$ 0	$ 7,352,676	$ 0