Operating Leases (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	$ 8.4	$ 8.4	$ 6.6
Operating Leases, Rent Expense, Sublease Rentals	0.3	0.3	0.2
Impairment of Leasehold			0.5
Leaseholds and Leasehold Improvements [Member]
Operating Leased Assets [Line Items]
Impairment of Leasehold			1.5
Leaseholds Sublease Revenue [Member]
Operating Leased Assets [Line Items]
Impairment of Leasehold			1.0
Leasehold Improvements [Member]
Operating Leased Assets [Line Items]
Impairment of Leasehold			$ 0.5