Derivatives and Hedging Activities (Narrative) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) instrument counterparty	Dec. 31, 2019 USD ($) instrument
Derivative [Line Items]
Derivative instruments in accumulated other comprehensive income reclassified to interest expense	$ 3,300
Derivative liability, notional amount	$ 490,000
Number of counterparties | counterparty	4
Counterparty in liability position | counterparty	4
Derivative liabilities	$ 139,000
Collateral against obligations	139,700
Derivatives Not Designated as a Hedging Instruments
Derivative [Line Items]
Credit derivatives, fair value	$ 88	$ 47
Derivatives Not Designated as a Hedging Instruments | Interest rate products
Derivative [Line Items]
Number of derivative instruments held (in instrument) | instrument	126	92
Derivative notional amount	$ 2,060,000	$ 1,610,000
Derivatives Not Designated as a Hedging Instruments | Credit contracts
Derivative [Line Items]
Number of derivative instruments held (in instrument) | instrument	13
Derivative notional amount	$ 109,000	$ 106,000
Designated as Hedging Instrument
Derivative [Line Items]
Number of outstanding derivatives | instrument	13