Derivative Financial Instruments (Summary of Interest Rate Derivatives) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Derivative Assets
Derivative Assets	$ 274,004	$ 296,848	$ 153,534
Derivative Liabilities
Gross Amounts Recognized	274,432	338,078	122,107
Interest rate contract
Derivative Assets
Derivative Assets	259,331	286,438	139,701
Less: Amounts offset in the Statements of Condition	0	0	0
Net amount presented in the Statements of Condition	259,331	286,438	139,701
Offsetting Derivative Positions	(55,838)	(64,100)	(19,557)
Collateral Posted	(181,884)	(194,666)	(70,807)
Net Credit Exposure	21,609	27,672	49,337
Derivative Liabilities
Gross Amounts Recognized	262,465	329,307	120,079
Less: Amounts offset in the Statements of Condition	0	0	0
Net amount presented in the Statements of Condition	262,465	329,307	120,079
Offsetting Derivative Positions	(55,838)	(64,100)	(19,557)
Collateral Posted	0	0	(257)
Net Credit Exposure	$ 206,627	$ 265,207	$ 100,265