Derivatives (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Incremental interest expense paid to interest rate swap counterparties	$ 0	$ 1,488
2011 Interest Rate Swap
Derivative [Line Items]
Derivative, Notional Amount		0
Notional amount of interest rate derivatives	0
Interest Rate Cash Flow Hedge Liability at Fair Value	$ 0	$ 0