Commitments and Contingencies - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Apr. 01, 2017 USD ($)	Jun. 30, 2018 USD ($) sites	Dec. 28, 2013 USD ($)	Dec. 30, 2017 USD ($)
Loss Contingencies [Line Items]
Document Period End Date		Jun. 30, 2018
Superfund Sites | sites		26
Environmental remediation. Period construction of treatment facility to be maintained		30 years
Centredale Site [Member]
Loss Contingencies [Line Items]
Environmental remediation costs, reserve		$ 77.7
Environmental Remediation Expense	$ 17.1
Centredale Site [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Environmental remediation costs deemed probable and reasonably estimable			$ 77.7
Centredale Site [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Environmental remediation costs deemed probable and reasonably estimable			$ 145.8
Property, Plant and Equipment, Other Types
Loss Contingencies [Line Items]
Environmental remediation costs, reserve		0.0		$ 176.1
Reserve for environmental remediation costs, current		28.7
Reserve for environmental remediation costs, noncurrent		222.0
Accrual for Environmental Loss Contingencies, EPA Funded Amount		12.2
Accrual for Environmental Loss Contingencies, Obligation After EPA Funding		238.5
Property, Plant and Equipment, Other Types | Minimum [Member]
Loss Contingencies [Line Items]
Environmental remediation costs deemed probable and reasonably estimable		218.1
Property, Plant and Equipment, Other Types | Maximum [Member]
Loss Contingencies [Line Items]
Environmental remediation costs deemed probable and reasonably estimable		$ 351.6