Statement of Cash Flows, Additional Disclosures (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Facility lease obligation		$ 0.2	$ 31.7
Capitalized and deferred interest		3.7
Capital lease obligations	0.7	2.9
Accrued interest income	$ 0.7	$ 1.4	$ 0.6