CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income	$ 262,632	$ 34,302
Adjustments to reconcile net income to net cash provided by operating activities:
Provision (reversal) for credit losses	(82,226)	189,731
Amortization of intangibles	1,051	2,473
Depreciation and amortization of premises and equipment	14,738	14,486
Net accretion of discounts and amortization of premiums and deferred fees	(12,361)	(27,269)
Interest capitalized on loans subject to the temporary payment moratorium	(2,855)	0
Share-based compensation	8,905	5,331
Impairment losses on long-lived assets	303	0
Fair value adjustments on mortgage servicing rights	(512)	5,229
Adjustments to indemnity reserves on loans sold	698	4,793
Earnings from investments under the equity method, net of dividends or distributions	(12,088)	(9,716)
Deferred income tax expense (benefit)	69,633	(23,152)
(Gain) loss on:
Disposition of premises and equipment and other productive assets	(4,443)	(1,369)
Proceeds from insurance claims	0	(366)
Sale of loans, including valuation adjustments on loans held-for-sale and mortgage banking activities	(4,977)	(4,944)
Sale of foreclosed assets, including write-downs	(6,090)	(4,850)
Acquisitions of loans held-for-sale	(63,261)	(51,163)
Proceeds from sale of loans held-for-sale	218,483	12,135
Net originations on loans held-for-sale	(327,742)	(58,166)
Net (increase) decrease in:
Trading debt securities	182,659	117,276
Equity securities	(3,197)	(273)
Accrued income receivable	(6,728)	4,794
Other assets	(4,942)	55,644
Net (decrease) increase in:
Interest payable	(8,498)	(9,488)
Pension and other postretirement benefits obligation	(1,071)	3,276
Other liabilities	(27,714)	(65,735)
Total adjustments	(72,235)	158,677
Net cash (used in) provided by operating activities	190,397	192,979
Cash flows from investing activities:
Net decrease (increase) in money market investments	72,284	(2,679,671)
Purchases of investment securities:
Available-for-sale	(6,828,725)	(1,550,746)
Equity	(1,296)	(15,219)
Proceeds from calls, paydowns, maturities and redemptions of investment securities:
Available-for-sale	4,492,494	3,838,754
Held-to-maturity	3,339	2,877
Proceeds from sale of investment securities:
Equity	64	12,321
Net repayments (disbursements) on loans	290,232	(192,839)
Proceeds from sale of loans	48,156	1,884
Acquisition of loan portfolios	(86,071)	(96,153)
Return of capital from equity method investments	682	131
Payments to acquire equity method investments	0	(440)
Acquisition of premises and equipment	(17,850)	(15,133)
Proceeds from insurance claims	0	366
Proceeds from sale of:
Premises and equipment and other productive assets	8,497	6,659
Foreclosed assets	24,968	19,413
Net cash used in investing activities	(1,993,226)	(667,796)
Net increase (decrease) in:
Deposits	1,881,314	1,047,341
Assets sold under agreements to repurchase	(34,469)	(14,612)
Other short-term borrowings	0	100,000
Payment of notes payable	(1,075)	(43,800)
Principal payments of finance leases	(1,133)	(538)
Proceeds from issuance of common stock	1,118	3,969
Payments for repurchase of redeemable preferred stock	0	(28,017)
Dividends paid	(34,053)	(29,726)
Net payments for repurchase of common stock	(279)	(500,222)
Payments related to tax witholding for share-based compensation	(3,663)	(2,579)
Net cash provided by financing activities	1,807,760	531,816
Net increase in cash and due from banks, and restricted cash	4,931	56,999
Cash and due from banks and restricted cash at beginning of period	497,094	394,323
Cash and due from banks and restricted cash at end of period	$ 502,025	$ 451,322