Fair-Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Interest expense	$ 4,625	$ 4,238	$ 9,060	$ 6,602
Interest Rate Current Swap [Member]
Derivative [Line Items]
Interest expense			500	600
Interest Rate Swap Buyouts [Member]
Derivative [Line Items]
Interest expense			$ 400	$ 100