Derivative and Hedging Activities Income impact of Fair Value and Cash Flow Hedge (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Interest Income [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	$ (13)	$ 0
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
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	(2,409)	0
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
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	2,396	0
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	$ 0	$ 0