Commitments and Contingencies (Details) - USD ($)			3 Months Ended
	Mar. 28, 2019	Nov. 19, 2018	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Oct. 27, 2017
Loss Contingencies [Line Items]
Self Insurance Reserve			$ 1,000,000
Reserves for estimated uninsured losses			400,000
Insurance reimbursements receivable					$ 20,000,000
Auto And General Liability Insurance [Member]
Loss Contingencies [Line Items]
Liability and cargo insurance coverage for claims			100,000,000
Insurance Claims
Loss Contingencies [Line Items]
Liability and cargo insurance coverage for claims			1,000,000
Cargo Claims
Loss Contingencies [Line Items]
Liability and cargo insurance coverage for claims			100,000
Uninsured Risk
Loss Contingencies [Line Items]
Reserves for estimated uninsured losses			28,000,000	$ 26,800,000
Federal Derivative Action [Member]
Loss Contingencies [Line Items]
Reserves for estimated uninsured losses					$ 22,000,000
Central Cal Agreement [Member]
Loss Contingencies [Line Items]
Liability and cargo insurance coverage for claims						$ 2,100,000
Reserves for estimated uninsured losses						1,800,000
Violation Of California Labor Laws
Loss Contingencies [Line Items]
Payments for settlement			9,200,000
Violation Of California Labor Laws | Legal Reserve [Member]
Loss Contingencies [Line Items]
Reserves for estimated uninsured losses			$ 1,600,000	$ 10,800,000
In re Roadrunner Transportation Systems, Inc. Securities Litigation [Member]
Loss Contingencies [Line Items]
Settlement to be paid		$ 20,000,000
Federal Derivative Action [Member]
Loss Contingencies [Line Items]
Settlement to be paid	$ 6,900,000
Settlement to be received	4,800,000	4,800,000
Minimum | Central Cal Agreement [Member]
Loss Contingencies [Line Items]
Indemnification claims owed to the Company						300,000
Maximum | Central Cal Agreement [Member]
Loss Contingencies [Line Items]
Indemnification claims owed to the Company						$ 1,000,000
Directors and Officers Liability Insurance [Member] | In re Roadrunner Transportation Systems, Inc. Securities Litigation [Member]
Loss Contingencies [Line Items]
Settlement to be paid		$ 17,900,000
Directors and Officers Liability Insurance [Member] | Federal Derivative Action [Member]
Loss Contingencies [Line Items]
Settlement to be received	$ 2,100,000