Lines of Credit and Financing Arrangements (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Lines of Credit and Financing Arrangements (Textuals) [Abstract]
Senior unsecured notes	$ 200.0	$ 200.0	$ 200.0
Line of Credit Facility [Line Items]
Maximum securitization, percent	100.00%	100.00%
Maximum securitization, amount		100.0
Average amount of beneficial interest sold		60.2
Average floating commercial paper rate	1.00%	1.00%	1.06%
Program fee		0.75%
Basis of unused fee	Unused fee is based on 102% of the maximum available amount less the beneficial interest sold and calculated 0.375% fixed rate throughout the term of the agreement
Restricted cash	0.5	0.5	12.2
Indebtedness to Adjusted EBITDA Ratio		3.5:1.0
Cash Flow to Net Interest Expense ratio		3.0:1.0
Senior Notes [Member]
Lines of Credit and Financing Arrangements (Textuals) [Abstract]
Fixed interest rate for senior unsecured notes	4.90%	4.90%
Senior unsecured notes			200.0
Default long term debt description of violation or event of default of revolving credit facility		The indenture governing the notes contains covenants limit our ability and the ability of the subsidiary guarantors to: create or incur certain liens; enter into certain sale and leaseback transactions; enter into certain mergers, consolidations and transfers of substantially all of our assets; and transfer certain properties.indenture also contains a cross default provision which is triggered if we default on other debt of at least $75 million in principal which is then accelerated, and such acceleration is not rescinded within 30 days of the notice date
Swingline Loans [Member]
Line of Credit Facility [Line Items]
Swingline loans facility	$ 50.0	$ 50.0