Self-Insurance (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Self-Insurance [Abstract]
Self-insured portions of programs accrued, total	$ 72.8	$ 62.4
Accrued self-insured portions of programs , noncurrent	37.7	29.2
Secured self-insured retention risk under workers' compensation, general liability, and professional liability programs with cash	17.3	18.0
Letters of credit associated to the secured self-insured retention risk	$ 40.7	$ 33.7

Carrying amount of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property that are expected to be paid after one year (or the normal operating cycle, if longer).

No definition available.

Name:	us-gaap_SelfInsuranceReserveNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant