Derivatives and Hedging Activities Effect of Derivative Instruments on Statement of Operations (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	[1]	$ 836	$ 67
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(21)	303
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net		5	(4)
Interest Expense [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(21)	303
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	[1]	$ 836	$ 67

[1] There was an additional $(4) thousand loss related to the ineffective portion for the three months ended as of March 31, 2017. The guidance in ASU 2017-12 requires that amounts in accumulated other comprehensive income that are included in the assessment of effectiveness should be reclassified into earnings in the same period in which the hedged forecasted transactions impact earnings. Transition guidance for this ASU further states that upon adoption, previously recorded cumulative ineffectiveness for cash flow hedges existing at the adoption date be eliminated by means of a cumulative-effect adjustment to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the initial application date. There was a $5 thousand reclassification related to the adoption of ASU 2017-12 effective January 1, 2018.