Risk Management - Risk Concentrations and Interest Rate Risk (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Interest rate contracts
Risk Management-Risk Concentrations and Interest Rate Risk
Number of agreements held | item		0
Amount of loss recognized in the income statement as an increase in interest expense	$ 1,500	$ 0	$ 500
Cash Flow Hedging
Risk Management-Risk Concentrations and Interest Rate Risk
Amount of loss recognized in the income statement as an increase in interest expense			499	$ (1,485)
Cash Flow Hedging | Interest expense Member | Interest rate contracts
Risk Management-Risk Concentrations and Interest Rate Risk
Amount of loss recognized in the income statement as an increase in interest expense			$ 499	$ (1,485)