Derivatives (Narrative) (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) contracts	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) contracts
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Counterparty default losses on forward contracts	$ 0	$ 0
Credit Derivatives [Line Items]
Commitments
Collateralized financings	739,000
Termination value of derivatives in a net liability position	261,100,000		270,000,000
Collateral required to be posted under agreements	85,100,000		89,500,000
Variation Margin Adjustment	$ 165,600,000		$ 209,500,000
Customer swaps offset by a swap executed on a bilateral basis with a counterparty bank	188		71
Counterparty bank cash as collateral on bilateral positions	$ 47,700,000		$ 51,900,000
Interest rate futures
Credit Derivatives [Line Items]
Derivative, notional amount	207,000,000
Mortgage-Backed Security
Credit Derivatives [Line Items]
Derivative, notional amount	10,000,000
Interest rate swaps
Credit Derivatives [Line Items]
Derivative, notional amount	$ 8,600,000,000		$ 7,300,000,000
Number of interest rate swaps | contracts	1,338		922
Commitments To Originate Loans Held For Sale
Credit Derivatives [Line Items]
Commitments	$ 39,898,000		$ 56,100,000
Interest rate forward sales commitments
Credit Derivatives [Line Items]
Commitments	$ 61,000,000		$ 104,000,000