CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net income	$ 509,682	$ 466,151	$ 292,990
Adjustments to reconcile net income to net cash provided by (used for) operating activities
Provision for credit losses	78,589	(59,263)	214,220
Depreciation, amortization and accretion, net	82,070	101,797	96,369
Deferred income tax expense (benefit)	22,057	(2,861)	(4,058)
Stock-based compensation expense (benefit)	31,748	16,177	(4,938)
Amortization of premium on securities, net	2,416	6,391	10,881
Accretion of discount and deferred fees on loans, net	(19,565)	(83,434)	(81,604)
Mortgage servicing rights fair value changes, net of economic hedge	(36,609)	16,515	63,343
Non-designated derivatives fair value changes, net	1,691	(569)	(484)
Originations and purchases of mortgage loans held-for-sale	(2,799,000)	(6,803,777)	(8,004,730)
Early buy-out exercises of mortgage loans held-for-sale guaranteed by U.S. government agencies, net of subsequent paydowns or payoffs	80,158	88	(297,599)
Proceeds from sales of mortgage loans held-for-sale	3,146,442	7,441,705	7,624,799
Bank owned life insurance (“BOLI”) loss (income)	806	(5,812)	(4,488)
(Increase) decrease in trading securities, net	(66)	(390)	397
Decrease (increase) in brokerage customer receivables, net	9,681	(8,632)	(863)
Gains on mortgage loans sold	(43,391)	(214,085)	(339,127)
Losses on investment securities, net, and dividend reinvestment on equity securities	20,427	1,059	2,373
Losses (gains) on sales of premises and equipment, net, and sale of related deposit liabilities	2,845	(3,614)	421
Gains on sales and fair value adjustments of other real estate owned, net	(792)	(2,792)	(1,421)
(Increase) decrease in accrued interest receivable and other assets, net	(91,585)	187,743	(131,870)
Increase in accrued interest payable and other liabilities, net	377,396	78,475	46,924
Net Cash Provided by (Used for) Operating Activities	1,375,000	1,130,872	(518,465)
Investing Activities:
Proceeds from maturities and calls of available-for-sale securities	386,259	1,290,126	1,613,143
Proceeds from maturities and calls of held-to-maturity securities	210,958	307,971	879,713
Proceeds from sales of available-for-sale securities	0	192,227	502,250
Proceeds from sales of equity securities with readily determinable fair value	31,753	9,759	6,530
Proceeds from sales and capital distributions of equity securities without readily determinable fair value	1,330	2,685	1,857
Purchases of available-for-sale securities	(2,762,171)	(842,170)	(1,998,380)
Purchases of held-to-maturity securities	(910,964)	(2,873,691)	(125,220)
Purchases of equity securities with readily determinable fair value	(59,495)	(9,060)	(45,735)
Purchases of equity securities without readily determinable fair value	(17,429)	(9,265)	(5,118)
(Redemptions) purchases of FHLB and FRB stock, net	(89,381)	210	(34,849)
Distributions from (contributions to) investments in partnerships, net	4,765	(2,107)	76
Net cash paid in business combinations	0	(585,402)	0
Proceeds from sale of other real estate owned	3,954	16,927	10,776
Decrease (increase) in securities purchased under resale agreements with terms exceeding three months, net	700,000	(700,000)	0
Decrease (increase) in interest-bearing deposits with banks, net	3,382,366	(569,205)	(2,636,581)
Increase in loans, net	(4,320,225)	(2,101,121)	(5,290,668)
Redemption of BOLI	960	332	3,428
Purchases of premises and equipment, net	(53,449)	(57,075)	(63,646)
Net Cash Used for Investing Activities	(3,490,769)	(5,928,859)	(7,182,424)
Financing Activities:
Increase in deposit accounts, net	806,947	5,006,801	6,985,964
Increase (decrease) in other borrowings, net	125,135	(27,784)	88,596
Increase in Federal Home Loan Bank advances, net	1,075,000	12,629	553,500
Cash payments to settle contingent consideration liabilities recognized in business combinations	0	(16,583)	(4,523)
Proceeds from the issuance of common stock, net	285,729	0	0
Proceeds from the issuance of preferred stock, net	0	0	277,613
Issuance of common shares resulting from exercise of stock options and employee stock purchase plan	11,233	19,824	15,059
Common stock repurchases under authorized program	0	(9,540)	(92,055)
Common stock repurchases for tax withholdings related to stock-based compensation	(304)	0	(1,377)
Dividends paid	(108,210)	(98,629)	(85,890)
Net Cash Provided by Financing Activities	2,195,530	4,886,718	7,736,887
Net Increase in Cash and Cash Equivalents	79,761	88,731	35,998
Cash and Cash Equivalents at Beginning of Period	411,205	322,474	286,476
Cash and Cash Equivalents at End of Period	490,966	411,205	322,474
Cash paid during the year for:
Interest	239,209	156,868	257,408
Income taxes, net	153,499	178,575	105,268
Business combinations:
Fair value of assets acquired, including cash and cash equivalents	0	591,409	0
Value ascribed to goodwill and other intangible assets	0	9,275	0
Fair value of liabilities assumed	0	6,007	0
Non-cash activities
Transfer to other real estate owned from loans	$ 10,018	$ 5,837	$ 13,239