Derivative Instruments Derivative Instruments - Assets and liabilities presented on a net basis due to the right of offset (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Asset, Fair Value, Gross Asset	$ 117	$ 479
Derivative Asset gross amount offset	(73)	(29)
Net amount of assets presented	44	450
Derivative Liability, Fair Value, Gross Liability	11	279
Derivative liability gross amount offset	0	(35)
Net amount of liabilities presented	$ 11	$ 244