Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2012	Jun. 29, 2019
Site Contingency [Line Items]
Litigation Settlement, Amount	$ 110,000
Environmental Costs Recovered		$ 37,000
Huntsville Site [Member]
Site Contingency [Line Items]
Environmental Remediation Expense To Date		6,600
Additional Expected Project Expenditures Low Estimate		3,800
Additional Expected Project Expenditures High Estimate		10,000
Norco Site [Member] | Remediation, Project Management, Regulatory Oversight, and Investigative and Feasability Studies [Member]
Site Contingency [Line Items]
Environmental Remediation Expense To Date		72,200
Additional Expected Project Expenditures Low Estimate		8,500
Additional Expected Project Expenditures High Estimate		$ 19,200