Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Capital Lease Obligations [Abstract]
Capital lease obligations	$ 0.2	$ 0.3
Capital lease obligations, current	0.1	0.2
Capital lease obligations, noncurrent	0.1	0.1
Credit Facility, Wells Fargo Bank [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	20.0
Line of credit maximum capacity for issuance letters of credit	10.0
Credit agreement, expiration date	July 1, 2012
Available remaining borrowing capacity	20.0	20.0
Outstanding letters of credit	$ 0	$ 0