Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations Percentage of Total	100.00%	100.00%
Description of Defined Contribution Pension and Other Postretirement Plans	Pension-plan benefits are based on the employee's age at retirement, years of service and highest earnings in a consecutive 72 semi-monthly pay period during the 10 years preceding retirement.
Defined Benefit Plan, Accumulated Benefit Obligation	$ 106.9	$ 78.3
Change in benefit obligation
Benefit payments	(1.3)	(0.2)
Change in plan assets
Beginning Balance	44.2	30.9
Company contributions to the plan	5.6	14.8
Ending Balance	55.3	44.2	30.9
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	(0.2)	(0.2)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	(2.2)
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Contribution Plan, Cost Recognized	6.4	5.8	4.2
Pension [Member]
Change in benefit obligation
Benefit obligation at January 1,	129.7	104.1	78.0
Change in plan assumptions	8.4	19.6
Benefit payments	(2.7)	(0.2)
Actuarial loss (gain)	10.8	(0.7)
Change in plan assets
Beginning Balance	44.2	30.9
Actual gain (loss) on plan assets	6.9	(1.3)
Company contributions to the plan	6.9	14.8
Underfunded status (current and long-term)	(74.4)	(59.9)
Ending Balance	55.3	44.2	30.9
Amounts recognized in balance sheets
Accounts payable and accrued expenses	(3.2)	(1.3)
Other long-term liabilities	(71.2)	(58.6)
Total amount recognized in balance sheet	(74.4)	(59.9)
Amounts recognized in AOCI
Net actuarial loss (gain)	32.6	18.6
Prior service cost	35.1	42.6
Total amount recognized in AOCI	67.7	61.2
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	4.0	2.9	1.3
Interest cost	5.1	4.5	2.1
Expected return on plan assets	(3.6)	(2.6)	(1.1)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	2.2	0	0
Amortization of prior service costs	5.3	5.3	2.6
Amortization of actuarial loss	1.9	0	0
Periodic expense	14.9	10.1	4.9
Pension and other postretirement plans adjustments:
Current period actuarial loss (gain)	15.9	22.9	(4.2)
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	(1.9)	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax	0	0	50.4
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Benefit Cost, before Tax	(5.3)	(5.3)	(2.6)
Defined Benefit Plan, Curtailments	(2.2)	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	6.5	17.6	43.6
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	7.3
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	5.0
Defined Benefit Plan, Amortization of Net Gains (Losses)	2.3
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate	3.88%	4.54%
Rate of increase in compensation	3.60%	3.60%
Discount rate	4.38%	5.80%	5.70%
Expected long-term return on plan assets	7.25%	7.50%	7.50%
Rate of increase in compensation	3.60%	3.60%	3.60%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	5.7
2014	5.3
2015	4.9
2016	5.6
2017	5.2
2018 through 2021	40.9
Pension [Member] | Funded Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to pension plan	5.6
Expected to contribute to pension plans	8.1
Pension [Member] | Unfunded Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to pension plan	1.3
Expected to contribute to pension plans	3.2
Postretirement benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected to contribute to pension plans	0.2
Change in benefit obligation
Benefit obligation at January 1,	6.7	5.9	4.5
Change in plan assumptions	0	0
Benefit payments	0	0
Actuarial loss (gain)	0.4	1.0
Change in plan assets
Beginning Balance	0	0
Actual gain (loss) on plan assets	0	0
Company contributions to the plan	0	0
Underfunded status (current and long-term)	(6.7)	(5.9)
Ending Balance	0	0	0
Amounts recognized in balance sheets
Accounts payable and accrued expenses	(0.2)	0
Other long-term liabilities	(6.5)	(5.9)
Total amount recognized in balance sheet	(6.7)	(5.9)
Amounts recognized in AOCI
Net actuarial loss (gain)	1.3	1.0
Prior service cost	3.4	3.8
Total amount recognized in AOCI	4.7	4.8
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0.1	0.1	0.1
Interest cost	0.3	0.3	0.1
Expected return on plan assets	0	0	0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	0
Amortization of prior service costs	0.3	0.3	0.2
Amortization of actuarial loss	0.1	0	0
Periodic expense	0.8	0.7	0.4
Pension and other postretirement plans adjustments:
Current period actuarial loss (gain)	0.4	1.0	0
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	(0.1)	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax	0	0	4.3
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Benefit Cost, before Tax	(0.4)	(0.3)	(0.1)
Defined Benefit Plan, Curtailments	0	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	(0.1)	0.7	4.2
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	0.5
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	0.4
Defined Benefit Plan, Amortization of Net Gains (Losses)	0
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate	4.10%	4.70%
Rate of increase in compensation	3.60%	4.00%
Discount rate	4.70%	5.80%	5.70%
Rate of increase in compensation	0.00%
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2013	0.2
2014	0.2
2015	0.2
2016	0.3
2017	0.3
2018 through 2021	1.8
Active Employees [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Number of Employees Covered	145
Percent of Active Employees [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Number of Employees Covered	0
Non-active Employees [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Number of Employees Covered	70
Level 1 [Member]
Change in plan assets
Ending Balance	0	0
Level 2 [Member]
Change in plan assets
Ending Balance	0	0
Level 3 [Member]
Change in plan assets
Ending Balance	55.3	44.2
Estimate of Fair Value, Fair Value Disclosure [Member]
Change in plan assets
Ending Balance	55.3	44.2
Domestic Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations Percentage of Total	40.00%	40.00%
Domestic Equity Securities [Member] | Level 1 [Member]
Change in plan assets
Ending Balance	0	0
Domestic Equity Securities [Member] | Level 2 [Member]
Change in plan assets
Ending Balance	0	0
Domestic Equity Securities [Member] | Level 3 [Member]
Change in plan assets
Ending Balance	22.2	17.6
Domestic Equity Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Change in plan assets
Ending Balance	22.2	17.6
Cash and Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations Percentage of Total	0.00%	0.00%
Cash and Cash Equivalents [Member] | Level 1 [Member]
Change in plan assets
Ending Balance	0	0
Cash and Cash Equivalents [Member] | Level 2 [Member]
Change in plan assets
Ending Balance	0	0
Cash and Cash Equivalents [Member] | Level 3 [Member]
Change in plan assets
Ending Balance	0.2	0
Cash and Cash Equivalents [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Change in plan assets
Ending Balance	0.2	0
Foreign Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations Percentage of Total	30.00%	29.00%
Foreign Equity Securities [Member] | Level 1 [Member]
Change in plan assets
Ending Balance	0	0
Foreign Equity Securities [Member] | Level 2 [Member]
Change in plan assets
Ending Balance	0	0
Foreign Equity Securities [Member] | Level 3 [Member]
Change in plan assets
Ending Balance	16.7	13.0
Foreign Equity Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Change in plan assets
Ending Balance	16.7	13.0
Debt Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations Percentage of Total	30.00%	31.00%
Debt Securities [Member] | Level 1 [Member]
Change in plan assets
Ending Balance	0	0
Debt Securities [Member] | Level 2 [Member]
Change in plan assets
Ending Balance	0	0
Debt Securities [Member] | Level 3 [Member]
Change in plan assets
Ending Balance	16.2	13.6
Debt Securities [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Change in plan assets
Ending Balance	16.2	13.6
Realized Gain (Loss) on Sale of Investments [Member]
Change in plan assets
Actual gain (loss) on plan assets	0.7	0.3
Unrealized Gain (Loss or Write-down) [Member]
Change in plan assets
Actual gain (loss) on plan assets	$ 6.3	$ (1.4)