Segment Information (Identifiable Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	$ 1,255,790	$ 1,056,203	$ 768,892
Eliminations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	(304,311)	(243,263)	(84,178)
U.S. [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	1,127,692	931,396	714,110
Europe [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	403,838	341,618	108,894
Other International [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	$ 28,571	$ 26,452	$ 30,066