Segment Information (Identifiable Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	$ 712,801	$ 455,315
U.S. [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	675,349	419,841
U.K. [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	83,386	70,750
Other International [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	16,626	17,674
Eliminations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Identifiable Assets	$ (62,560)	$ (52,950)