Long-Term Debt - Revolving Loan (Details) $ in Millions		3 Months Ended		6 Months Ended
	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Debt, short-term and long-term		$ 3,318.2		$ 3,318.2		$ 3,267.8
Net loss on extinguishments of long-term debt		0.0	$ 0.0	57.4	$ 0.0
Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Debt, short-term and long-term		54.0		54.0		0.0
Undrawn letters of credit		1.0		1.0
Borrowing base		1,650.0		1,650.0
Additional borrowing capacity		1,016.0		1,016.0
Cash availability, minimum liquidity		$ 125.0		$ 125.0
Cash availability, percentage of borrowing base		10.00%		10.00%
Minimum liquidity, amount		$ 100.0		$ 100.0
Basis spread on variable rate (as percent)				1.00%
Debt instrument term	5 years
Maximum borrowing capacity	$ 1,450.0					1,250.0
Maximum aggregate increase	$ 300.0
Unused portion of revolving credit facility, fees	0.0025
Potential margin reduction	0.0025
Net loss on extinguishments of long-term debt				$ 1.0
Deferred finance costs, net and unamortized premium		4.0		4.0
Senior secured term loan facility
Debt Instrument [Line Items]
Debt, short-term and long-term		1,475.6		1,475.6		$ 1,483.0
Net loss on extinguishments of long-term debt		14.0
Deferred finance costs, net and unamortized premium		$ 5.0		$ 5.0
Minimum | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Consolidated fixed charge coverage ratio		1		1
Federal Funds Effective Swap Rate | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)				0.50%
London Interbank Offered Rate (LIBOR) | Minimum | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)				1.25%
London Interbank Offered Rate (LIBOR) | Maximum | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)				1.75%
Base Rate | Minimum | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)				0.25%
Base Rate | Maximum | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Basis spread on variable rate (as percent)				0.75%
Accounts Payable, Inventory Financing | Senior secured asset-based revolving credit facility
Debt Instrument [Line Items]
Amount owed under Revolving loan financing agreement		$ 444.0		$ 444.0