Financial Instruments - Narrative (Details) - Interest rate swaps - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financial Instruments (Textual) [Abstract]
Notional Amount	$ 75,000
Fixed LIBOR interest rate	1.08%
Accumulated Other Comprehensive Income (Loss), Amortization of Gain (Loss) on Derivative Instrument, Included in Net Income	$ 400	$ 400