CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 66,904	$ 84,831	$ 68,668
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	3,726		4,009
Provision for credit losses	448	(14,648)	1,974
Share-based compensation expense	5,530		3,105
Loss on sales and disposals of premises and equipment	37		7
Net amortization on securities	5,023		5,983
Net (accretion) of discounts/premiums for acquired loans and deferred loan fees/costs	(7,353)		(10,833)
Gain on sales of investment securities available-for-sale	(2,134)		(4,046)
Loss on debt extinguishment	0		503
Gain on sales of loans	(1,494)		(361)
Deferred income tax expense	7,887		14,650
Income from bank owned life insurance, net	(2,617)		(1,675)
Amortization of intangible assets	3,592	3,880	4,143
Originations of loans held-for-sale	(18,769)		(7,768)
Proceeds from the sales of and principal payments from loans held-for-sale	19,486		970
Change in accrued expenses and other liabilities, net	15,207		(34,203)
Change in accrued interest receivable and other assets, net	36,904		60,176
Net cash provided by operating activities	132,377		105,302
Cash flows from investing activities:
Net decrease in interest-bearing time deposits with financial institutions	0		137
Loan originations and payments, net	(430,951)		128,540
Proceeds from loans held-for-sale previously classified as portfolio loans	0		449
Proceeds from prepayments and maturities of securities held-to-maturity	3,750		1,807
Purchase of securities available-for-sale	(499,168)		(364,542)
Proceeds from prepayments and maturities of securities available-for-sale	77,817		162,568
Proceeds from sales of securities available-for-sale	647,557		179,386
Proceeds from the sales of premises and equipment	0		4
Proceeds from surrender of bank owned life insurance	0		1,307
Purchase of premises and equipment	(2,308)		(1,465)
Change in FHLB, FRB, and other stock, at cost	(95)		(202)
Funding of CRA investments, net	(701)		(3,873)
Net cash (used in) provided by investing activities	(204,099)		104,116
Cash flows from financing activities:
Net increase in deposit accounts	573,634		525,830
Net change in short-term borrowings	(358,000)		0
Proceeds from long-term borrowings	400,000		0
Repayments of long-term borrowings	0		(21,503)
Cash dividends paid	(31,142)		(28,287)
Repurchase and retirement of common stock	0		(6,897)
Proceeds from exercise of stock options	334		620
Restricted stock surrendered and canceled	(8,548)		(5,279)
Net cash provided by financing activities	576,278		464,484
Net increase in cash and cash equivalents	504,556		673,902
Cash and cash equivalents, beginning of period	304,703		880,766
Cash and cash equivalents, end of period	809,259	$ 304,703	1,554,668
Supplemental cash flow disclosures:
Interest paid	3,927		10,890
Income taxes (refunded) paid, net	(11,944)		77
Noncash investing activities during the period:
Transfers of investment securities from available-for-sale to held-to-maturity	618,678		0
Recognition of operating lease right-of-use assets	(459)		0
Recognition of operating lease liabilities	459		0
Receivable on unsettled security sales	13,464		0
Due on unsettled security purchases	$ 0		$ (11,286)