Derivatives and Balance Sheet Offsetting (Narative) (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Offsetting [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 10,400
Gain on termination of interest rate collar	34,400
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	40,040
Commitments To Originate Loans Held For Sale Member
Balance Sheet Offsetting [Line Items]
Commitments and contingent liabilities (Note 10)	30,600	$ 31,900
Interest rate Forward Sales Contracts
Balance Sheet Offsetting [Line Items]
Commitments and contingent liabilities (Note 10)	27,500	26,500
Not Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Derivative, Notional Amount	587,900	$ 597,900
Designated as Hedging Instrument [Member] \| Interest rate collar [Domain]
Balance Sheet Offsetting [Line Items]
Derivative, Notional Amount	500,000
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Balance Sheet Offsetting [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	$ 40,040

[Line Items] for Balance Sheet Offsetting [Table]

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- Definition

Gain on termination of interest rate collar

+ References

No definition available.

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Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur.

+ References

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

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- Definition

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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Amount, before effects of master netting arrangements, of financial assets loaned to entities in exchange for collateral and funds outstanding borrowed in the form of a financial asset repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same financial assets at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement.

+ References

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