Fair Value Measurement-Estimated Fair Values (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted investments, held to maturity, amortized cost	[1]	$ 22,864	$ 23,215
Restricted Investments, Estimated Fair Value	[1]	22,851	23,190
2015 Agreement, New Term Loan A, due July 2020, Carrying Amount		594,062	679,177
Accounts receivable securitization, due January 2019, Carrying Amount		299,196	223,927
Revolving line of credit, Carrying Amount	[2],[3]	50,000	200,000
Deferred loan costs		3,486	4,264
2015 Agreement, New Term Loan A [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
2015 Agreement, New Term Loan A, due July 2020, Carrying Amount	[2],[4]	592,819	668,055
2015 Agreement, New Term Loan A, due July 2020, Fair Value	[4]	594,250	669,750
Deferred loan costs		1,431	1,695
2015 RSA [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Accounts receivable securitization, due January 2019, Carrying Amount	[5]	299,196	223,927
Accounts receivable securitization, due January 2019, Fair Value	[5]	300,000	225,000
Deferred loan costs		800	1,100
2015 Agreement, New Revolver [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revolving line of credit, Carrying Amount		50,000	200,000
Revolving line of credit, Fair Value		$ 50,000	$ 200,000

[1] Restricted investments are included in "Restricted investments, held to maturity, amortized cost."

[2] Refer to Note 15 for information regarding the fair value of long-term debt.

[3] The Company additionally had outstanding letters of credit, primarily related to workers' compensation and self-insurance liabilities of $97.0 million and $95.0 million under the New Revolver at September 30, 2016 and December 31, 2015, respectively.

[4] The New Term Loan A is included in "Current portion of long-term debt" and "Long-term debt, less current portion." Carrying value is net of $1.4 million and $1.7 million DLCs as of September 30, 2016 and December 31, 2015, respectively.

[5] Carrying value is net of $0.8 million and $1.1 million DLCs as of September 30, 2016 and December 31, 2015, respectively.