Commitments and Contingencies (Details) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012 USD ($)	Mar. 31, 2012 GBP (£)
Loss Contingencies [Line Items]
Damages sought, amount	$ 8,800	£ 5,500
Damages sought, interest at statutory rate (per annum)	8.00%	8.00%
IRS proposed adjustments to tax years 2000 through 2002, before penalty and interest	$ 16,500
Potential penalty, percentage of tax assessment	20.00%	20.00%

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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+ Details