Fair Value Measurement - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Derivatives Details
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			$ 100
Net unrealized gain (loss) on cash flow hedge	$ (261)	$ (507)	(209)	$ (1,398)
Swap [Member]
Derivatives Details
Derivative, Gain (Loss) on Derivative, Net		300		1,600
Designated as Hedging Instrument [Member] | Level 2
Derivatives Details
Derivative Asset	$ 700		$ 700		$ 800
Derivative Liability		2,100		2,100
Not Designated as Hedging Instrument [Member] | Level 2
Derivatives Details
Derivative Asset		$ 1,700		$ 1,700