Debt and Financing (Details)		6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 27, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 1,055,400,000		$ 1,055,400,000
Premium/(Discount), Debt			(3,200,000)		(3,200,000)
Debt Issuance Cost			(11,700,000)		(11,700,000)
Book Value			1,040,500,000		1,040,500,000
Book Value, Current Maturities			(16,600,000)		(16,600,000)	$ (15,900,000)
Par Value, Excluding Current Maturities			1,038,800,000		1,038,800,000
Debt Instrument, Unamortized Discount (Premium), Net, Noncurrent Maturities			3,200,000		3,200,000
Book Value, Excluding Current Maturities			1,023,900,000		1,023,900,000	1,046,500,000
Debt Instrument, Borrowing Base Cash Release As Percent Of Collateral	$ 0.10	$ 0.15
Cash and cash equivalents			276,400,000	$ 210,700,000	276,400,000	173,800,000	$ 171,100,000
Operating leases, future minimum payments due			323,800,000		323,800,000
Acquisition of property and equipment			(75,400,000)	$ (71,800,000)
Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			1,040,500,000		1,040,500,000	1,062,400,000
Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			1,022,200,000		1,022,200,000	979,600,000
Term Loan
Debt Instrument [Line Items]
Long-term Debt, Gross			680,800,000		680,800,000
Premium/(Discount), Debt			(3,200,000)		(3,200,000)
Debt Issuance Cost			(9,700,000)		(9,700,000)
Book Value			667,900,000		667,900,000
Debt Instrument, Gross, Current Maturities			(7,000,000)		(7,000,000)
Premium/(Discount), Current Maturities			0		0
Deferred Finance Costs, Current, Net			0		0
Book Value, Current Maturities			$ (7,000,000)		$ (7,000,000)
Stated Interest Rate			8.00%		8.00%
Average Effective Interest Rate			8.20%		8.20%
Term Loan | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 667,900,000		$ 667,900,000	669,000,000
Term Loan | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			655,500,000		655,500,000	594,600,000
Line of Credit [Member] | 2014 ABL Facility Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			0		0
Premium/(Discount), Debt			0		0
Debt Issuance Cost			0		0
Book Value			0		0
Borrowing base			412,600,000		412,600,000
Line of credit facility, total cash and availability			55,000,000		55,000,000
Secured Second A&R CDA [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			29,000,000		29,000,000
Premium/(Discount), Debt			0		0
Debt Issuance Cost			(200,000)		(200,000)
Book Value			$ 28,800,000		$ 28,800,000
Average Effective Interest Rate			7.30%		7.30%
Stated Interest Rate, Minimum			3.30%
Stated Interest Rate, Maximum			18.30%
Unsecured Second A&R CD [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 73,200,000		$ 73,200,000
Premium/(Discount), Debt			0		0
Debt Issuance Cost			(400,000)		(400,000)
Book Value			$ 72,800,000		$ 72,800,000
Average Effective Interest Rate			7.30%		7.30%
Stated Interest Rate, Minimum			3.30%
Stated Interest Rate, Maximum			18.30%
Lease Financing Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 272,400,000		$ 272,400,000
Premium/(Discount), Debt			0		0
Debt Issuance Cost			(1,400,000)		(1,400,000)
Book Value			271,000,000		271,000,000
Debt Instrument, Gross, Current Maturities			(9,600,000)		(9,600,000)
Premium/(Discount), Current Maturities			0		0
Deferred Finance Costs, Current, Net			0		0
Book Value, Current Maturities			$ (9,600,000)		$ (9,600,000)
Average Effective Interest Rate			12.00%		12.00%
Stated Interest Rate, Minimum			9.00%
Stated Interest Rate, Maximum			18.20%
Lease Financing Obligations [Member] | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 271,000,000		$ 271,000,000	276,300,000
Lease Financing Obligations [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			268,300,000		268,300,000	282,900,000
Letter of Credit [Member] | 2014 ABL Facility Credit Agreement [Member]
Debt Instrument [Line Items]
Letters of credit outstanding, amount			357,600,000		357,600,000
10 percent of Borrowing Base			41,300,000		41,300,000
10 percent of line cap			45,000,000		45,000,000
Other Debt Obligations [Member] | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			101,600,000		101,600,000	117,100,000
Other Debt Obligations [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 98,400,000		$ 98,400,000	$ 102,100,000
Credit Agreement Amendment, September 2014 [Member]
Debt Instrument [Line Items]
Maximum Total Leverage Ratio, September 30, 2016			3.75
Maximum Total Leverage Ratio, December 31, 2017			3.5
Maximum Total Leverage Ratio, March 31, 2017			3.25
Maximum Total Leverage Ratio, June 30, 2017			3.25
Maximum Total Leverage Ratio, September 30, 2017			3.25
Maximum Total Leverage Ratio, December 31, 2017 and thereafter			3.00
Debt Instrument, Total Leverage Ratio					3.45
2014 ABL Facility Credit Agreement [Member]
Debt Instrument [Line Items]
Amount able to be drawn			$ 13,700,000
2014 ABL Facility Credit Agreement [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, total cash and availability			290,100,000.0		$ 290,100,000.0
Revenue Equipment [Member]
Debt Instrument [Line Items]
Operating lease commitment			$ 95,200,000		$ 95,200,000
Operating lease term			5 years
London Interbank Offered Rate (LIBOR) [Member] | Term Loan
Debt Instrument [Line Items]
Floor interest rate			1.00%		1.00%
Basis Spread On Variable Rate, Total Leverage Ratio Less Than 3.25			7.00%
London Interbank Offered Rate (LIBOR) [Member] | ABL Facility [Member]
Debt Instrument [Line Items]
Interest rate decrease		50.00%
Basis spread on variable rate	1.75%	2.25%