Long-term Debt (Other Long-term Debt) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010 Lexington	Dec. 31, 2009 Lexington	Jun. 30, 2010 Lexington
Capital Leases of Lessee [Line Items]
Non-cash gain in substantial modification of existing building finance obligation	$ 0	$ (3.6)	$ 5.7	$ (3.6)	$ 5.7
Acquisition cost allocation, extinguishment of debt						$ 43.1