Long Term Debt (Issuance of Debt Instrument) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Debt Instrument [Line Items]
Fixed Charge Coverage Ratio	2.00 to 1.0
2018 Notes
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	Feb. 10, 2010
Debt Instrument, Face Amount	$ 725.0
Proceeds from Issuance of Debt	689.7
Debt Instrument, Interest Rate, Stated Percentage	8.875%
Debt Instrument, Call Date, Earliest	Feb. 15, 2014
Debt Instrument Call Date Mid	Feb. 15, 2015
Debt Instrument, Call Date, Latest	Feb. 15, 2016
Debt Instrument, Maturity Date	Feb. 15, 2018
Selling Price Of Debt Instrument	97.907%
Debt Instrument, Interest Rate, Effective Percentage	9.25%
Redemption Price 2018 Note 1	104.438%
Redemption Price 2018 Note 2	102.219%
Redemption Price 2018 Note 3	100.00%
2022 Notes
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	May 24, 2012
Debt Instrument, Face Amount	250.0
Proceeds from Issuance of Debt	$ 245.1
Debt Instrument, Interest Rate, Stated Percentage	7.125%
Debt Instrument, Call Date, Earliest	Jun. 01, 2017
Debt Instrument Call Date Mid	Jun. 01, 2018
Debt Instrument Call Date 1 Mid	Jun. 01, 2019
Debt Instrument, Call Date, Latest	Jun. 01, 2020
Selling Price Of Debt Instrument	100.00%
Debt Instrument, Interest Rate, Effective Percentage	7.125%
Redemption Price For Early Redepemption	107.125%
Redemption Amount	35.00%
Redemption Price 1	103.563%
Redemption Price 2	102.375%
Redemption Price 3	101.188%
Redemption Price 4	100.00%
Principal Outstanding After Early Redemption	65.00%
Redemption Days	180