Derivative and Hedging Activities Cumulative Basis Adjustment for Fair Value Hedges (Details) - Designated as Hedging Instrument $ in Thousands	Jun. 30, 2019 USD ($)
Balance Sheet Recording of Fair Value Hedge [Line Items]
Carrying Amount of the Hedged Assets/(Liabilities)	$ 500,000
Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets/(Liabilities)	6,000
Amortized cost basis of hedged asset	994,000
Carrying Value [Member]
Balance Sheet Recording of Fair Value Hedge [Line Items]
Carrying Amount of the Hedged Assets/(Liabilities)	505,659	[1]
adjustment [Member]
Balance Sheet Recording of Fair Value Hedge [Line Items]
Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets/(Liabilities)	$ 5,659	[1]

[1] (a) These amounts include the amortized cost basis of closed portfolios used to designated hedging relationships in which the hedged item is the last layer expected to be remaining at the end of the hedging relationship. At June 30, 2019, the amortized cost basis of the closed portfolios used in these hedging relationships was $994 million; the positive cumulative basis adjustments associated with these hedging relationships was $6 million; and the amounts of the designated hedged items were $500 million.