Business Acquisitions (Narrative) (Details) - USD ($)				3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Aug. 05, 2019	Nov. 21, 2018	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Sep. 28, 2019
Business Acquisition [Line Items]
Contingent consideration assumed in acquisition				$ 19,180,000	$ 0	$ 19,180,000	$ 0	$ 0
Revenue				196,225,000	$ 232,209,000	613,531,000	$ 668,436,000
R&D Acquisition
Business Acquisition [Line Items]
Consideration paid at closing	$ 58,280,000
Estimated contingent consideration	16,903,000
Revenue				14,105,000		28,813,000
Acquisition costs						2,493,000
Goodwill, expected tax deductible amount				0		0
Intangible assets	42,251,000
Endevco
Business Acquisition [Line Items]
Consideration paid at closing		$ 70,000,000
Revenue				5,000,000		12,500,000
Intangible assets		25,700,000
Cash paid at closing		$ 68,330,000
E2M Technologies B.V.
Business Acquisition [Line Items]
Consideration paid at closing			$ 79,772,000
Revenue								29,554,000
Acquisition costs								$ 1,287,000
Goodwill, expected tax deductible amount				$ 0		$ 0
Intangible assets			43,989,000
Cash paid at closing			$ 80,287,000
Maximum | R&D Acquisition
Business Acquisition [Line Items]
Earn-out payments	$ 26,000,000