Debt and Financing (Details)		3 Months Ended	6 Months Ended		12 Months Ended
		Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($) shares	Jun. 30, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($)	Mar. 25, 2015 $ / shares shares	Dec. 31, 2013 USD ($)
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 1,089,200,000		$ 1,089,200,000	$ 1,116,200,000
Premium/(Discount), Debt			(5,000,000)		(5,000,000)	(6,300,000)
Book Value			1,084,200,000		1,084,200,000	1,109,900,000
Book Value, Current Maturities			(14,800,000)		(14,800,000)	(31,100,000)
Par Value, Excluding Current Maturities			1,074,400,000		1,074,400,000	1,084,500,000
Debt Instrument, Unamortized Discount (Premium), Net, Noncurrent Maturities			5,000,000		5,000,000	5,700,000
Book Value, Excluding Current Maturities			1,069,400,000		1,069,400,000	1,078,800,000
Cash and cash equivalents		$ 173,900,000	196,000,000	$ 173,900,000	$ 196,000,000	171,100,000		$ 176,300,000
Series B Notes outstanding principal and interest							17,900,000.0
Series B Notes conversion price per share | $ / shares							$ 18.00
Common stock shares converted for Series B Notes | shares							994,689
Expense Related to Fair Value of Incremental Shares Converted			$ 600,000
Cash Repayment to Series B Notes holders			300,000.0		300,000.0
Amortization of premiums and discounts on debt			$ 1,400,000	20,100,000
Operating leases, future minimum payments, remainder of fiscal year			43,600,000		$ 43,600,000
Operating leases, future minimum payments due			215,600,000		215,600,000
Acquisition of property and equipment			(42,600,000)	(24,700,000)
Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			1,084,200,000		1,084,200,000	1,109,900,000
Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			1,078,000,000		1,078,000,000	1,104,400,000
2014 Term Loan [Domain] [Domain]
Debt Instrument [Line Items]
Long-term Debt, Gross			689,500,000		689,500,000
Premium/(Discount), Debt			(5,000,000)		(5,000,000)
Book Value			684,500,000		684,500,000
Debt Instrument, Gross, Current Maturities			(7,000,000)		(7,000,000)	(7,000,000)
Premium/(Discount), Current Maturities			0		0	0
Book Value, Current Maturities			$ (7,000,000)		$ (7,000,000)	(7,000,000)
Stated Interest Rate			8.25%		8.25%
Average Effective Interest Rate			8.50%		8.50%
2014 Term Loan [Domain] [Domain] | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 684,500,000		$ 684,500,000	687,300,000
2014 Term Loan [Domain] [Domain] | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			674,000,000		674,000,000	685,400,000
Restructured Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						693,000,000
Premium/(Discount), Debt						(5,700,000)
Book Value						$ 687,300,000
Stated Interest Rate						8.25%
Average Effective Interest Rate						8.50%
Line of Credit [Member] | 2014 ABL Facility Credit Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	[1]		0		0
Premium/(Discount), Debt	[1]		0		0
Book Value	[1]		0		0
Borrowing base			436,400,000		436,400,000	$ 445,500,000
Line of credit facility, total cash and availability			$ 73,800,000		73,800,000	71,200,000
Line of Credit [Member] | ABL facility - Term A [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	[2]					0
Premium/(Discount), Debt	[2]					0
Book Value	[2]					0
Pension Contribution Deferral Obligation [Member]
Debt Instrument [Line Items]
Stated Interest Rate, Minimum
Stated Interest Rate, Maximum
Letter of Credit [Member] | 2014 ABL Facility Credit Agreement [Member]
Debt Instrument [Line Items]
Letters of credit outstanding, amount			$ 362,600,000		362,600,000	374,300,000
10 percent of Borrowing Base			43,700,000		43,700,000
10 percent of line cap			45,000,000		45,000,000
Unused borrowing capacity, amount						27,100,000
Senior Notes [Member] | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			0		0	17,100,000
Senior Notes [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 0		$ 0	17,700,000
Senior Notes [Member] | Senior B Notes [Domain]
Debt Instrument [Line Items]
Long-term Debt, Gross						17,700,000
Premium/(Discount), Debt						(600,000)
Book Value						$ 17,100,000
Stated Interest Rate						10.00%
Average Effective Interest Rate						25.60%
Senior Notes [Member] | Senior B Notes
Debt Instrument [Line Items]
Debt conversion price, future period | $ / shares			$ 18.5334		$ 18.5334
Number of shares converted per thousand, future period | shares			53.9567
Conversion ratio			0.0539567
Debt conversion, amount		$ 0		$ 1,200,000
Conversion of stock, shares converted | shares				75,900
Interest Expense, Debt				$ 400,000
Make whole premium				200,000
Amortization of premiums and discounts on debt				$ 200,000
Senior Notes [Member] | Series B Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Gross, Current Maturities						$ (17,700,000)
Premium/(Discount), Current Maturities						600,000
Book Value, Current Maturities						(17,100,000)
Secured Second A&R CDA [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 45,000,000		$ 45,000,000	47,000,000
Premium/(Discount), Debt			0		0	0
Book Value			$ 45,000,000		$ 45,000,000	$ 47,000,000
Stated Interest Rate, Minimum		3.25%	3.30%
Stated Interest Rate, Maximum		18.30%	18.30%
Average Effective Interest Rate			7.30%		7.30%	7.30%
Unsecured Second A&R CD [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 73,200,000		$ 73,200,000	$ 73,200,000
Premium/(Discount), Debt			0		0	0
Book Value			$ 73,200,000		$ 73,200,000	$ 73,200,000
Stated Interest Rate, Minimum			3.30%
Stated Interest Rate, Maximum			18.30%
Average Effective Interest Rate			7.30%		7.30%	7.30%
Lease Financing Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 281,500,000		$ 281,500,000	$ 285,100,000
Premium/(Discount), Debt			0		0	0
Book Value			281,500,000		281,500,000	285,100,000
Debt Instrument, Gross, Current Maturities			(7,800,000)		(7,800,000)	(6,800,000)
Premium/(Discount), Current Maturities			0		0	0
Book Value, Current Maturities			$ (7,800,000)		$ (7,800,000)	$ (6,800,000)
Stated Interest Rate, Minimum			10.00%			10.00%
Stated Interest Rate, Maximum			18.20%			18.20%
Average Effective Interest Rate			12.00%		12.00%	12.00%
Lease Financing Obligations [Member] | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 281,500,000		$ 281,500,000	$ 285,100,000
Lease Financing Obligations [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			288,500,000		288,500,000	282,200,000
Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						200,000
Premium/(Discount), Debt						0
Book Value						200,000
Debt Instrument, Gross, Current Maturities						(200,000)
Premium/(Discount), Current Maturities						0
Book Value, Current Maturities						(200,000)
Other Debt Obligations [Member] | Carrying Amount [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			118,200,000		118,200,000	120,400,000
Other Debt Obligations [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value			$ 115,500,000		$ 115,500,000	119,100,000
Credit Agreement Amendment, September 2014 [Member]
Debt Instrument [Line Items]
Maximum Total Leverage Ratio, June 30, 2015			4.75
Maximum Total Leverage Ratio, September 30, 2015			4.50
Maximum Total Leverage Ratio, December 31, 2015			4.25
Maximum Total Leverage Ratio, March 31, 2016			4.00
Maximum Total Leverage Ratio, June 30, 2016			3.75
Maximum Total Leverage Ratio, September 30, 2016			3.75
Maximum Total Leverage Ratio, December 31, 2016			3.50
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					3.33
2014 ABL Facility Credit Agreement [Member]
Debt Instrument [Line Items]
Amount able to be drawn			$ 30,100,000.0
2014 ABL Facility Credit Agreement [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, total cash and availability			226,100,000.0		$ 226,100,000.0	$ 198,200,000.0
Revenue Equipment [Member]
Debt Instrument [Line Items]
Operating lease commitment			$ 78,600,000		$ 78,600,000
Operating lease term			5 years

[1] There were no amounts drawn on the ABL Facility at any time during the six months ended June 30, 2015.

[2] There were no amounts drawn on the ABL Facility at any time during the twelve months ended December 31, 2014.