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The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Amount of increase in the fair value of derivatives recognized in the income statement.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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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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No definition available.

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Amount of decrease in the fair value of derivatives recognized in the income statement.

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Nominal or face amount used to calculate payment on derivative.

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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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Fair value as of the balance sheet date of interest rate derivative assets, net of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet.

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Fair value of financial and nonfinancial obligations.

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of open derivatives, commodity, or energy contracts, held at each balance sheet date, that was included in earnings for the period.

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Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Derivative Financial Instruments
Notional Amount	$ 20,901,604		$ 20,901,604		$ 19,342,657
Estimated Fair Value Gain			489,085		813,899
Estimated Fair Value Loss			485,007		804,832
Interest Rate Derivative Assets, at Fair Value	480,600		480,600		802,800
Interest Rate Derivative Liabilities, at Fair Value	480,600		480,600		802,700
Interest Rate Derivatives, at Fair Value, Net	5		5		17
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Fair value of forward commitments	(485,007)		(485,007)		(804,832)
Mortgage loan pipeline
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	432,063		432,063		510,730
Expected closures
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	385,210		385,210		411,273
Cash flow hedge \| Borrower
Derivative Financial Instruments
Collateral provided	372,500		372,500
Interest rate contracts
Derivative Financial Instruments
Notional Amount	20,200,000		20,200,000		18,600,000
Mortgage servicing rights hedging \| Non-designated hedges
Derivative Financial Instruments
Notional Amount	185,000		185,000		149,000
Estimated gain (loss) on fair value			(2,900)	$ 389
Mortgage servicing rights hedging \| Non-designated hedges \| Other Assets and Other Liabilities
Derivative Financial Instruments
Notional Amount	185,000		185,000		149,000
Estimated Fair Value Gain					119
Estimated Fair Value Loss			2,903
Mortgage loan pipeline commitments hedging
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	6,319		6,319		15,328
Mortgage loan pipeline commitments hedging \| Non-designated hedges \| Other Assets
Derivative Financial Instruments
Notional Amount	466,500		466,500		528,500
Estimated Fair Value Gain			8,485		11,017
Forward commitments
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	466,500		466,500		528,500
Fair value of forward commitments	2,166		2,166		(4,311)
Customer swaps \| Cash flow hedge \| Investment securities - available for sale
Derivative Financial Instruments
Collateral provided	429,100		429,100
Foreign exchange swaps
Derivative Financial Instruments
Gain or loss recorded	0	$ 0
Interest rate swap \| Fair Value Hedging \| Counterparty
Derivative Financial Instruments
Notional Amount	16,000		16,000		16,400
Gain or loss recorded	0		0
Interest rate swap \| Fair Value Hedging \| Other Liabilities \| Counterparty
Derivative Financial Instruments
Notional Amount	16,042		16,042		16,439
Estimated Fair Value Loss			1,499		2,086
Interest rate swap \| Non-designated hedges \| Other Assets and Other Liabilities \| Borrower
Derivative Financial Instruments
Notional Amount	10,112,896		10,112,896		9,324,359
Estimated Fair Value Gain			480,600		802,717
Estimated Fair Value Loss			52,959		46
Interest rate swap \| Non-designated hedges \| Other Assets and Other Liabilities \| Counterparty
Derivative Financial Instruments
Notional Amount	$ 10,121,166		10,121,166		9,324,359
Estimated Fair Value Gain					46
Estimated Fair Value Loss			$ 427,646		$ 802,700