Financial Instruments - Notional Amounts (Details) - Interest rate swaps - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivatives designated as and not designated as cash flow hedges:
Notional Amount	$ 75,000
Not designated as cash flow hedge
Derivatives designated as and not designated as cash flow hedges:
Notional Amount	0	$ 75,000
Interest Rate Derivative Assets, at Fair Value	0	0
Interest Rate Derivative Liabilities, at Fair Value	$ 0	$ 299