Supplemental Guarantor Information Condensed Consolidating Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	$ 435.0	$ 366.3	$ 317.4
Capital expenditures	(55.0)	(47.1)	(41.4)
Payments to Acquire Equity Method Investments	(86.8)	0	0
Premium payments on interest rate cap agreements	(2.1)	0	(0.3)
Net cash used in investing activities	(164.8)	(47.1)	(41.7)
Proceeds from borrowings under revolving credit facility	0us-gaap_ProceedsFromLinesOfCredit	63.0us-gaap_ProceedsFromLinesOfCredit	289.0us-gaap_ProceedsFromLinesOfCredit
Repayments of borrowings under revolving credit facility	0us-gaap_RepaymentsOfLinesOfCredit	(63.0)us-gaap_RepaymentsOfLinesOfCredit	(289.0)us-gaap_RepaymentsOfLinesOfCredit
Repayments of long-term debt	(15.4)us-gaap_RepaymentsOfSecuredDebt	(51.1)us-gaap_RepaymentsOfSecuredDebt	(201.0)us-gaap_RepaymentsOfSecuredDebt
Proceeds from issuance of long-term debt	1,175.0	1,535.2	135.7
Payments to extinguish long-term debt	(1,299.0)us-gaap_RepaymentsOfLongTermDebt	(2,047.4)us-gaap_RepaymentsOfLongTermDebt	(243.2)us-gaap_RepaymentsOfLongTermDebt
Payments of debt financing costs	(21.9)us-gaap_PaymentsOfFinancingCosts	(6.1)us-gaap_PaymentsOfFinancingCosts	(2.1)us-gaap_PaymentsOfFinancingCosts
Net change in accounts payable-inventory financing	75.5	7.4	(29.5)
Payment of incentive compensation plan withholding taxes	0	(24.1)	0
Proceeds from Stock Options Exercised	1.3	0	0
Net proceeds from issuance of common shares	0	424.7	0
Proceeds from Coworker Stock Purchase Plan	5.8	0	0
Dividends paid	(33.6)us-gaap_PaymentsOfDividendsCommonStock	(7.3)us-gaap_PaymentsOfDividendsCommonStock	0us-gaap_PaymentsOfDividendsCommonStock
Excess Tax Benefit from Share-based Compensation, Financing Activities	0.3	0.6	0
Net cash provided by (used in) financing activities	(112.0)	(168.3)	(338.0)
Effect of exchange rate changes on cash and cash equivalents	(1.8)	(0.7)	0.3
Net increase (decrease) in cash and cash equivalents	156.4	150.2	(62.0)
Cash and cash equivalents - beginning of period	188.1	37.9	99.9
Cash and cash equivalents - end of period	344.5	188.1	37.9
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	(20.9)	0	0
Parent Guarantor [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	0	(15.2)	0
Capital expenditures	0	0	0
Payments to Acquire Equity Method Investments	0
Premium payments on interest rate cap agreements			0
Net cash used in investing activities	0	0	0
Proceeds from borrowings under revolving credit facility		0	0
Repayments of borrowings under revolving credit facility		0	0
Repayments of long-term debt	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Payments to extinguish long-term debt	0	0	0
Payments of debt financing costs	0	0	0
Net change in accounts payable-inventory financing	0	0	0
Payment of incentive compensation plan withholding taxes		0
Proceeds from Stock Options Exercised	0
Net proceeds from issuance of common shares		424.7
Proceeds from Coworker Stock Purchase Plan	0
Dividends paid	(33.6)	(7.3)
Excess Tax Benefit from Share-based Compensation, Financing Activities	0
Advances to (from) affiliates	33.6	(402.2)	0
Other financing activities		0	0
Net cash provided by (used in) financing activities	0	15.2	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents - beginning of period	0	0	0
Cash and cash equivalents - end of period	0	0	0
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	0
Payments for Derivative Instrument, Financing Activities	0
Subsidiary Issuer [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	(120.4)	(130.3)	(204.3)
Capital expenditures	(47.9)	(40.8)	(27.0)
Payments to Acquire Equity Method Investments	(86.8)
Premium payments on interest rate cap agreements			(0.3)
Net cash used in investing activities	(157.7)	(40.8)	(27.3)
Proceeds from borrowings under revolving credit facility		63.0	289.0
Repayments of borrowings under revolving credit facility		(63.0)	(289.0)
Repayments of long-term debt	(15.4)	(51.1)	(201.0)
Proceeds from issuance of long-term debt	1,175.0	1,535.2	135.7
Payments to extinguish long-term debt	(1,299.0)	(2,047.4)	(243.2)
Payments of debt financing costs	(21.9)	(6.1)	(2.1)
Net change in accounts payable-inventory financing	0	0	0
Payment of incentive compensation plan withholding taxes		(4.0)
Proceeds from Stock Options Exercised	1.3
Net proceeds from issuance of common shares		0
Proceeds from Coworker Stock Purchase Plan	5.8
Dividends paid	0	0
Excess Tax Benefit from Share-based Compensation, Financing Activities	0.3
Advances to (from) affiliates	581.9	892.6	486.0
Other financing activities		0.4	2.1
Net cash provided by (used in) financing activities	428.0	319.6	177.5
Effect of exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	149.9	148.5	(54.1)
Cash and cash equivalents - beginning of period	196.5	48.0	102.1
Cash and cash equivalents - end of period	346.4	196.5	48.0
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	(20.9)
Payments for Derivative Instrument, Financing Activities	2.1
Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	547.7	508.8	514.2
Capital expenditures	(7.1)	(6.2)	(14.0)
Payments to Acquire Equity Method Investments	0
Premium payments on interest rate cap agreements			0
Net cash used in investing activities	(7.1)	(6.2)	(14.0)
Proceeds from borrowings under revolving credit facility		0	0
Repayments of borrowings under revolving credit facility		0	0
Repayments of long-term debt	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Payments to extinguish long-term debt	0	0	0
Payments of debt financing costs	0	0	0
Net change in accounts payable-inventory financing	75.5	7.4	(29.5)
Payment of incentive compensation plan withholding taxes		(19.6)
Proceeds from Stock Options Exercised	0
Net proceeds from issuance of common shares		0
Proceeds from Coworker Stock Purchase Plan	0
Dividends paid	0	0
Excess Tax Benefit from Share-based Compensation, Financing Activities	0
Advances to (from) affiliates	(616.1)	(490.4)	(486.5)
Other financing activities		0	0
Net cash provided by (used in) financing activities	(540.6)	(502.6)	(516.0)
Effect of exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	(15.8)
Cash and cash equivalents - beginning of period	0	0	15.8
Cash and cash equivalents - end of period	0	0	0
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	0
Payments for Derivative Instrument, Financing Activities	0
Non-Guarantor Subsidiaries [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	11.8	5.5	1.3
Capital expenditures	0	(0.1)	(0.4)
Payments to Acquire Equity Method Investments	0
Premium payments on interest rate cap agreements			0
Net cash used in investing activities	0	(0.1)	(0.4)
Proceeds from borrowings under revolving credit facility		0	0
Repayments of borrowings under revolving credit facility		0	0
Repayments of long-term debt	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Payments to extinguish long-term debt	0	0	0
Payments of debt financing costs	0	0	0
Net change in accounts payable-inventory financing	0	0	0
Payment of incentive compensation plan withholding taxes		(0.5)
Proceeds from Stock Options Exercised	0
Net proceeds from issuance of common shares		0
Proceeds from Coworker Stock Purchase Plan	0
Dividends paid	0	0
Excess Tax Benefit from Share-based Compensation, Financing Activities	0
Advances to (from) affiliates	0.6	0	0.5
Other financing activities		0	0
Net cash provided by (used in) financing activities	0.6	(0.5)	0.5
Effect of exchange rate changes on cash and cash equivalents	(1.8)	(0.7)	0.3
Net increase (decrease) in cash and cash equivalents	10.6	4.2	1.7
Cash and cash equivalents - beginning of period	14.0	9.8	8.1
Cash and cash equivalents - end of period	24.6	14.0	9.8
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	0
Payments for Derivative Instrument, Financing Activities	0
Co-Issuer [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	0	0	0
Capital expenditures	0	0	0
Payments to Acquire Equity Method Investments	0
Premium payments on interest rate cap agreements			0
Net cash used in investing activities	0	0	0
Proceeds from borrowings under revolving credit facility		0	0
Repayments of borrowings under revolving credit facility		0	0
Repayments of long-term debt	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Payments to extinguish long-term debt	0	0	0
Payments of debt financing costs	0	0	0
Net change in accounts payable-inventory financing	0	0	0
Payment of incentive compensation plan withholding taxes		0
Proceeds from Stock Options Exercised	0
Net proceeds from issuance of common shares		0
Proceeds from Coworker Stock Purchase Plan	0
Dividends paid	0	0
Excess Tax Benefit from Share-based Compensation, Financing Activities	0
Advances to (from) affiliates	0	0	0
Other financing activities		0	0
Net cash provided by (used in) financing activities	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents - beginning of period	0	0	0
Cash and cash equivalents - end of period	0	0	0
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	0
Payments for Derivative Instrument, Financing Activities	0
Consolidating Adjustments [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	(4.1)	(2.5)	6.2
Capital expenditures	0	0	0
Payments to Acquire Equity Method Investments	0
Premium payments on interest rate cap agreements			0
Net cash used in investing activities	0	0	0
Proceeds from borrowings under revolving credit facility		0	0
Repayments of borrowings under revolving credit facility		0	0
Repayments of long-term debt	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Payments to extinguish long-term debt	0	0	0
Payments of debt financing costs	0	0	0
Net change in accounts payable-inventory financing	0	0	0
Payment of incentive compensation plan withholding taxes		0
Proceeds from Stock Options Exercised	0
Net proceeds from issuance of common shares		0
Proceeds from Coworker Stock Purchase Plan	0
Dividends paid	0	0
Advances to (from) affiliates	0	0	0
Other financing activities		0	0
Net cash provided by (used in) financing activities	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	(4.1)	(2.5)	6.2
Cash and cash equivalents - beginning of period	(22.4)	(19.9)	(26.1)
Cash and cash equivalents - end of period	(26.5)	(22.4)	(19.9)
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	0
Payments for Derivative Instrument, Financing Activities	0
Consolidated [Member]
Supplemental Guarantor Information [Line Items]
Net cash provided by (used in) operating activities	435.0	366.3	317.4
Capital expenditures	(55.0)	(47.1)	(41.4)
Payments to Acquire Equity Method Investments	(86.8)
Premium payments on interest rate cap agreements	(2.1)		(0.3)
Net cash used in investing activities	(164.8)	(47.1)	(41.7)
Proceeds from borrowings under revolving credit facility		63.0	289.0
Repayments of borrowings under revolving credit facility		(63.0)	(289.0)
Repayments of long-term debt	(15.4)	(51.1)	(201.0)
Proceeds from issuance of long-term debt	1,175.0	1,535.2	135.7
Payments to extinguish long-term debt	(1,299.0)	(2,047.4)	(243.2)
Payments of debt financing costs	(21.9)	(6.1)	(2.1)
Net change in accounts payable-inventory financing	75.5	7.4	(29.5)
Payment of incentive compensation plan withholding taxes		(24.1)
Proceeds from Stock Options Exercised	1.3
Net proceeds from issuance of common shares	5.8	424.7
Dividends paid	(33.6)	(7.3)
Excess Tax Benefit from Share-based Compensation, Financing Activities	0.3
Advances to (from) affiliates	0	0	0
Other financing activities		0.4	2.1
Net cash provided by (used in) financing activities	(112.0)	(168.3)	(338.0)
Effect of exchange rate changes on cash and cash equivalents	(1.8)	(0.7)	0.3
Net increase (decrease) in cash and cash equivalents	156.4	150.2	(62.0)
Cash and cash equivalents - beginning of period	188.1	37.9	99.9
Cash and cash equivalents - end of period	344.5	188.1	37.9
Payment of accrued charitable contribution related to the MPK Coworker Incentive Plan II	$ (20.9)

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Amount of cash inflow from realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

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The cash inflow from the additional capital contribution to the entity.

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The cash inflow associated with the amount received from holders to acquire the entity's shares under incentive and share awards other than stock option exercises. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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No definition available.

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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The net cash inflow or outflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

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The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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