Risk Management and Derivatives (Interest Rate Hedges) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	$ (14,699)	$ 847	$ (85)
Designated as hedge | Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income		$ 400