Commitments and Contingencies (Details) $ in Thousands				12 Months Ended
	Jun. 25, 2020 USD ($)	Feb. 18, 2020 USD ($)	Feb. 07, 2013 plaintiff	Dec. 31, 2020 USD ($) employee agreement warehouse	Dec. 31, 1994 USD ($)	Dec. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Letter of credit amount outstanding				$ 21,700		$ 23,000
Number of employees | employee				16,300
Number of warehouses | warehouse				238
Number of collective bargaining agreements | agreement				73
Number of collective bargaining agreements, agreements renewed | agreement				19
Number of collective bargaining agreements expiring in 2021 | agreement				11
Number of warehouses where collective bargaining agreements are expiring in 2021 | warehouse				13
Kansas Breach of Settlement Agreement
Loss Contingencies [Line Items]
Litigation settlement, awarded to other party					$ 58,700
Number of plaintiffs appealing dismissal | plaintiff			1
Preferred Freezer Services, LLC Litigation
Loss Contingencies [Line Items]
Litigation settlement from other party		$ 550
Damages sought	$ 400,000
Surety Bond
Loss Contingencies [Line Items]
Outstanding surety bond				$ 10,100		$ 4,300
Unionized Employees Concentration Risk
Loss Contingencies [Line Items]
Number of warehouses | warehouse				84
Number of Employees | Unionized Employees Concentration Risk
Loss Contingencies [Line Items]
Collective-bargaining arrangement, percentage of participants				47.00%
Number of Employees | Unionized Employees, Under Renegotiation Concentration Risk
Loss Contingencies [Line Items]
Collective-bargaining arrangement, percentage of participants				3.30%