Loans and Leases - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable	$ 93,600	$ 106,500
Jumbo residential mortgage loans	34,466,408	34,497,464
Residual value of leased assets	344,300	277,100
Depreciation and amortization	437,585	308,638	$ 204,778
Premises and equipment, net	470,131	533,138
Recorded investment in loans and leases sold, including accrued interest	2,446,969	2,888,408	1,238,018
Gains on sale of loans, net	86,776	26,308	33,695
Impairment charges on interest-only strips	224	62	$ 661
Consumer Loan Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Jumbo residential mortgage loans	10,524,207
Consumer Loan Portfolio \| Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gains on sale of loans, net		27,500
Legacy TCF
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans and leases sold, including accrued interest		1,100,000
Premises and equipment leased under finance leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Depreciation and amortization	73,200	76,400
Premises and equipment, net	326,900	$ 289,700
Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Jumbo residential mortgage loans	1,100,000
PCD loans	$ 0

Financing Receivable, Interest Receivable

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Represents the amount of impairment losses recorded during the period related to interest-only strips.

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The recorded investment of the loans sold during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of purchased credit protection expected to cover future payments under the credit risk derivative.

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The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

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Amount, before allowance for credit loss, of financing receivable.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount of residual asset covered by residual value guarantee. Excludes guarantee considered to be lease payments for lessor.

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