Derivatives and Hedging (Narrative) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) derivative_contract	Dec. 31, 2017 USD ($) derivative_contract
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive loss	$ (9,608)	$ (6,170)
Gain (Loss) On Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive loss	$ 4,900	$ 7,400
Interest Rate Contracts [Member] | Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Number of active interest rate contracts held | derivative_contract	0	3
Number of interest rate derivatives terminated | derivative_contract	3
Notional amount of interest rate fair value hedge derivatives	$ 200,000	$ 200,000
Gain due to the probability that the related hedged forecasted transactions would no longer occur	3,400
Derivative, fixed Interest rate		1.50%
Cash flow hedge gain (loss) to be amortized within 12 months	$ 900