Restructuring and Cost Management Plans - Amounts Related to Restructuring Costs Payable (Details) - USD ($) $ in Thousands		6 Months Ended				12 Months Ended
		Sep. 29, 2018		Jul. 01, 2017		Apr. 01, 2017
Q4 FY17 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		$ 0		$ 24,660		$ 17,074
Restructuring Reserve [Roll Forward]
Restructuring Reserve Start		139
Restructuring Reserve End		81				4,135
Q4 FY17 Restructuring Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		0		4,925		1,337
Restructuring Reserve [Roll Forward]
Restructuring Reserve Start		139
Restructuring Reserve End		81				3,247
Q4 FY17 Restructuring Plan [Member] | Current Asset Impairments and Other Gross Profit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		0	[1]	$ 14,947	[2]	13,278	[1]
Restructuring Reserve [Roll Forward]
Restructuring Reserve Start	[1]	0
Restructuring Reserve End	[1]	0				0
Q4 FY17 Restructuring Plan [Member] | Site Closures and Non-current Asset Impairments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		2,284
Chelmsford Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		0				409
Restructuring Reserve [Roll Forward]
Restructuring Reserve Start		290
Restructuring Reserve End		$ 94				$ 861

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjllOTFmNDhmOGZmNzQwNjE4YjZhYzU2YmI1NDBiNTNlfFRleHRTZWxlY3Rpb246NjIwMjM3RUJCQkM4NDczRjNFQUMxQTg2RURBM0IyRTIM}

[2] (1) Current asset impairments include inventory charges recorded in cost of sales.