Debt - ABL Credit Facility and Covenants (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016
Debt Instrument [Line Items]
Debt, gross		$ 2,174,300,000
Line of Credit | ABL Credit Facility
Debt Instrument [Line Items]
Fixed charge coverage ratio (not less than)		1
Line of Credit | Other Borrowings
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 10,000,000.0
Remaining Capacity			$ 7,400,000
Line of credit facility, percentage ratio of interest rate to prevailing base lending rates	110.00%
Senior Secured Revolving Credit Facility | Line of Credit | ABL Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 1,750,000,000
Cash proceeds reinvestment percentage (less than)		100.00%
Cash proceeds reinvestment period		365 days
Covenant terms, available loan commitments (less than)		$ 250,000,000
Covenant terms, collateral, percentage of capital stock		65.00%
Maximum payment of dividends (not to exceed)		$ 200,000,000
Remaining Capacity		597,200,000
Debt, gross		1,130,000,000	$ 910,000,000
Revolving Credit Facility | Line of Credit | ABL Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity				350,000,000
Letter of Credit | Line of Credit | ABL Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 250,000,000
Remaining Capacity		$ 227,200,000