Acquisitions - Narrative (Details) - USD ($) $ in Thousands							3 Months Ended		9 Months Ended
	Oct. 06, 2020	Jun. 30, 2020	Jun. 15, 2020	Apr. 17, 2020	Feb. 24, 2020	Feb. 27, 2019	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Business Acquisition [Line Items]
Shares issued						$ 27,000
Merger and acquisition expenses							$ 100	$ 100	$ 1,500	$ 1,900
FTT Inc
Business Acquisition [Line Items]
Percentage of voting interests acquired						80.10%
FTT Core
Business Acquisition [Line Items]
Percentage of voting interests acquired						80.10%
FTT
Business Acquisition [Line Items]
Percentage of voting interests acquired						80.10%
Aggregate purchase price						$ 60,000
Total cash paid						33,000
Payment to Acquire Business, At Closing						17,700
Amount to be paid						$ 15,300
Payment period						3 years
Current liabilities						$ 7,500
Deferred tax liabilities						7,000
Revenue								16,300		37,700
Operating income								700		1,000
Merger and acquisition expenses								$ 0		$ 1,300
Cash paid						$ 20,700
FTT | Subsequent event
Business Acquisition [Line Items]
Working capital adjustments	$ 1,950
FTT | Common Stock
Business Acquisition [Line Items]
Number of shares issued (in shares)						1,825,406				1,825,406
FTT | Customer relationships
Business Acquisition [Line Items]
Intangible assets acquired						$ 19,700
Useful life						13 years
FTT | In-process research and development
Business Acquisition [Line Items]
Intangible assets acquired						$ 8,500
FTT | Contracts and backlog
Business Acquisition [Line Items]
Intangible assets acquired						$ 2,100
Useful life						2 years
FTT | Trade names
Business Acquisition [Line Items]
Intangible assets acquired						$ 500
Useful life						2 years
Technical Directions, Inc.
Business Acquisition [Line Items]
Working capital adjustments							300
Cash paid					$ 10,500
Optimized Performance Machining, Inc. (OPM)
Business Acquisition [Line Items]
Working capital adjustments							30
Cash paid				$ 1,800
CPI ASC Signal Division, Inc.
Business Acquisition [Line Items]
Current liabilities		$ 9,100
Deferred tax liabilities		1,300
Revenue							10,200
Operating income							700
Merger and acquisition expenses							$ 100		$ 1,100
Cash paid		34,900	$ 35,000
Intangible assets		$ 4,300
CPI ASC Signal Division, Inc. | Customer relationships
Business Acquisition [Line Items]
Useful life		5 years
Intangible assets		$ 2,000
CPI ASC Signal Division, Inc. | Trade names
Business Acquisition [Line Items]
Useful life		1 year
Intangible assets		$ 100
CPI ASC Signal Division, Inc. | Developed technology and technical know-how
Business Acquisition [Line Items]
Useful life		7 years
Intangible assets		$ 2,200