Fair-Value Measurements (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Interest expense	$ 12,254	$ 15,227	$ 18,118
Interest Rate Swap [Member]
Derivative [Line Items]
Interest expense	$ 1,900	$ 1,900
Hedge effectiveness, percent	100.00%