Derivative and Hedging Activities Income impact of Fair Value and Cash Flow Hedge (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest Income [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge		$ 53	$ 5	$ 219	$ (13)
Other Operating Income (Expense) [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge		0	0	0	0
Not Designated as Hedging Instrument, Economic Hedge [Member] | Interest Income [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge		4,165	(2,133)	6,222	(2,409)
Not Designated as Hedging Instrument, Economic Hedge [Member] | Other Operating Income (Expense) [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge		0	0	0	0
Designated as Hedging Instrument | Interest Income [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	[1]	(4,112)	2,138	(6,003)	2,396
Designated as Hedging Instrument | Other Operating Income (Expense) [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	[1]	$ 0	$ 0	$ 0	$ 0

[1] (a) Includes net settlements on the derivatives.