Debt and Financing (Details) | Jun. 30, 2016USD ($) | Jun. 27, 2016USD ($) | Sep. 30, 2016USD ($) | Sep. 30, 2015USD ($) | Sep. 30, 2016USD ($) | Dec. 31, 2015USD ($) | Dec. 31, 2014USD ($) |
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 | | | | |
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 | | $ 290,100,000 | | |
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% | | | | | |