Derivative Financial Instruments - CF Hedges Gain, Loss (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Gains and losses from derivatives      
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness $ 0 $ 0 $ 0
Cash Flow Hedges      
Gains and losses from derivatives      
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives 2,173 3,336 2,758
Cash Flow Hedges | Interest Rate Swaps      
Gains and losses from derivatives      
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives $ 2,173 3,353 2,766
Cash Flow Hedges | Interest Rate Cap      
Gains and losses from derivatives      
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivatives   $ (17) $ (8)