Senior Credit Facilities (Details) (USD $)
In Millions, unless otherwise specified

9 Months Ended

Sep. 30, 2012

Dec. 31, 2011

Covenants [Abstract]

Covenant limitation incur additional debt in excess of

$ 250.0

Maximum pro forma senior leverage ratio

2.50

Consolidated funded debt outstanding

527.0

Consolidated EBITDA

401.1

Outstanding indebtedness less cash in excess of

25.0

Adjusted Consolidated EBITDA

551.5

Consolidated fixed charges

331.4

Pro forma consolidated leverage ratio

2.75

Financial Covenants Ratios (Table Details) [Abstract]

Required consolidated leverage ratio, maximum

3.25

Actual consolidated leverage ratio

1.31

Required fixed charge coverage ratio, minimum

1.35

Actual fixed charge coverage ratio

1.66

Interest Rate [Abstract]

Interest accrued at Prime rate plue %, minimum

0.50%

Interest accrued at Prime rate plus %, maximum

1.50%

Interest accrued at Eurodollar rate plus %, minimum

1.50%

Interest accrued at Eurodollar rate plus %, maximum

2.50%

Interest period

Interest periods range from seven days (for borrowings under the revolving credit facility only) to one, two, three or six months, at our election.

Margin on Eurodollar rate

1.75%

Margin on prime rate

0.75%

Commitment fee percentage, minimum

0.30%

Commitment fee percentage, maximum

0.50%

Senior Credit Facilities (Details) [Abstract]

Event of default-3rd party ownership % of our voting stock

35.00%

Event of default-not satisfied or bonded judgment in excess of

50.0

Maximum period allowed for pending judgment to satisfy or bond (in days)

30

Maximum fund drawn on individual occasion

100.0

Maximum total amount outstanding

221.0

Debt Instrument [Line Items]

Term loan, maximum facility

250.0

Term loan, amount outstanding

218.8

237.5

Line of credit, maximum facility

500.0

Line of credit, amount outstanding

65.0

185.0

Letters of credit, outstanding

116.2

318.8

Senior credit facilities, maximum amount

$ 750.0