Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows From Operating Activities
Net income	$ 581,992	$ 428,287	$ 277,538
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	38,180	36,436	27,276
Amortization of other intangible assets	24,155	25,857	11,336
Amortization of tax credit investments	15,367	10,961	6,770
Net premium amortization on investment securities	7,416	18,684	16,305
Accretion income related to acquired loans	(22,191)	(72,007)	(16,747)
Share-based compensation expense	27,910	28,656	7,497
Provision (release) for credit losses	58,887	144,799	(29,622)
Debt securities (gains) losses, net	6,265	88	(4,327)
Gain on sale of Visa Class B restricted shares	(21,635)	0	0
Gain on sale of health savings accounts	0	(90,673)	0
Net (gains) losses on sales of loans and other assets	(3,074)	13,114	(36,677)
Increase in cash surrender value of company-owned life insurance	(15,397)	(14,564)	(10,589)
Residential real estate loans originated for sale	(473,478)	(570,111)	(1,215,015)
Proceeds from sales of residential real estate loans	472,537	620,958	1,274,812
(Increase) decrease in interest receivable	(34,637)	(52,911)	1,198
(Increase) decrease in other assets	(66,070)	(40,518)	2,641
Increase (decrease) in accrued expenses and other liabilities	(79,885)	327,369	17,984
Net cash flows provided by (used in) operating activities	516,342	814,425	330,380
Cash Flows From Investing Activities
Cash received from merger, net	0	1,912,629	0
Sale of health savings accounts	0	(290,857)	0
Purchases of investment securities available-for-sale	(1,084,416)	(1,438,572)	(3,321,653)
Purchases of investment securities held-to-maturity	(1,941)	(170,675)	0
Purchases of Federal Home Loan Bank/Federal Reserve Bank stock	(99,158)	(147,394)	0
Purchases of equity securities	(28,408)	(6,348)	(11,000)
Proceeds from maturities, prepayments, and calls of investment securities    available-for-sale	1,066,266	1,284,814	1,511,510
Proceeds from sales of investment securities available-for-sale	96,506	20,032	198,886
Proceeds from maturities, prepayments, and calls of investment securities held-to-maturity	94,511	83,962	0
Proceeds from sales of Federal Home Loan Bank/Federal Reserve Bank stock	47,738	108,698	58
Proceeds from sales of equity securities	24,636	53,029	544
Loan originations and payments, net	(2,673,593)	(3,071,765)	206,145
Proceeds from sales of commercial loans	757,593	0	0
Proceeds from company-owned life insurance death benefits	16,252	10,361	3,375
Proceeds from sale of premises and equipment and other assets	3,513	4,480	29,244
Purchases of premises and equipment and other assets	(38,375)	(37,901)	(48,692)
Net cash flows provided by (used in) investing activities	(1,818,876)	(1,685,507)	(1,431,583)
Net increase (decrease) in:
Deposits	2,234,350	(435,717)	1,531,742
Federal funds purchased and interbank borrowings	(581,099)	581,213	(890)
Securities sold under agreements to repurchase	(147,598)	(94,665)	(38,891)
Other borrowings	16,938	177,146	36,187
Payments for maturities of Federal Home Loan Bank advances	(2,250,149)	(2,102,506)	(146,505)
Payments for modification of Federal Home Loan Bank advances	0	0	(2,156)
Proceeds from Federal Home Loan Bank advances	2,700,000	2,900,000	50,000
Cash dividends paid	(180,030)	(177,623)	(92,829)
Common stock repurchased	(44,308)	(71,182)	(3,731)
Common stock issued	1,076	809	583
Net cash flows provided by (used in) financing activities	1,749,180	777,475	1,333,510
Net increase (decrease) in cash and cash equivalents	446,646	(93,607)	232,307
Cash and cash equivalents at beginning of period	728,412	822,019	589,712
Cash and cash equivalents at end of period	$ 1,175,058	$ 728,412	$ 822,019