Multipemployer Pension and Postretirement Plans Multiemployer Pension Plans Trusts Funds (Details) - USD ($) $ in Millions		12 Months Ended
		Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Multiemployer Plans [Line Items]
Contributions		$ 7.0	$ 8.7	$ 10.4
Bakery And Confectionary Union And Industry International Pension Fund [Member]
Multiemployer Plans [Line Items]
Funding improvement or rehabilitation plan implementation status, insignificant	[1]	Implemented
Contributions, insignificant	[1]	$ 5.9	$ 5.9	6.5
Surcharge imposed, insignificant	[1]	Yes
Multiemployer Plan, Pension, Insignificant, Employees Covered by Collective-Bargaining Arrangement to All Entity's Employees, Percentage		80.00%
Plan number, insignificant	[1]	001
Certified zone status, insignificant	[1]	Red	Red
Certified zone status date, insignificant	[1]	Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plan, Pension, Insignificant, Collective-Bargaining Arrangement, Expiration Date	[1],[2]	Mar. 16, 2021
Employer Identification Number, insignificant	[1]	526118572
Bakery And Confectionary Union And Industry International Pension Fund [Member] | Minimum
Multiemployer Plans [Line Items]
Multiemployer Plan, Pension, Insignificant, Collective-Bargaining Arrangement, Expiration Date	[1],[2]	Dec. 17, 2020
Bakery And Confectionary Union And Industry International Pension Fund [Member] | Maximum
Multiemployer Plans [Line Items]
Multiemployer Plan, Pension, Insignificant, Collective-Bargaining Arrangement, Expiration Date	[1],[2]	Mar. 16, 2021
Central States Southeast And Southwest Areas Pension Fund [Member]
Multiemployer Plans [Line Items]
Funding improvement or rehabilitation plan, implementation status, significant		Implemented
Surcharge imposed, significant		Yes
Contributions, significant		$ 0.0	$ 1.3	1.9
Plan number, significant		001
Certified zone status, significant		Red	Red
Certified zone status date, significant		Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plan, Pension, Significant, Collective-Bargaining Arrangement, Expiration Date	[3]
Employer Identification Number, significant		366044243
Western Conference Of Teamsters Pension Trust [Member]
Multiemployer Plans [Line Items]
Funding improvement or rehabilitation plan implementation status, insignificant		NA
Contributions, insignificant		$ 0.9	$ 0.8	1.0
Surcharge imposed, insignificant		No
Plan number, insignificant		001
Certified zone status, insignificant		Green	Green
Certified zone status date, insignificant		Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plan, Pension, Insignificant, Collective-Bargaining Arrangement, Expiration Date	[4]	Mar. 26, 2022
Employer Identification Number, insignificant		916145047
Other Plans [Member]
Multiemployer Plans [Line Items]
Contributions, insignificant		$ 0.2	$ 0.7	$ 1.0
Multiemployer Plan, Pension, Insignificant, Collective-Bargaining Arrangement, Expiration Date	[5]

[1] The Company is party to multiple CBAs requiring contributions to this fund, each with its own expiration date. Over 80 percent of the Company’s participants in this fund are covered by a single CBA that expires on 4/16/2021.

[2] The Company does not expect 2021 contributions to be materially different than 2020.

[3] During 2019, the Company terminated CBAs covered by this fund. As a result, the Company has withdrawn from the fund and recognized expense for its estimated withdrawal liability. The Company does not expect to make 2021 contributions.

[4] The Company does not expect 2021 contributions to be materially different than 2020.

[5] During 2019, the Company terminated the CBAs covered by certain of these funds. As a result, for the impacted funds, the Company recognized expense for the estimated withdrawal liability in each year and no longer made contributions following the termination. The Company does not expect 2021 contributions to the remaining funds to be materially different from 2020.