Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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SUPPLEMENTAL FINANCIAL STATEMENT DATA - Equipment And Leasehold Improvements, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019	Dec. 27, 2019
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	$ 28,542		$ 28,542		$ 27,334
Accumulated depreciation and amortization	(15,751)		(15,751)		(15,283)
Total equipment and leasehold improvements, net	12,791		12,791		12,051
Amortization	5,466	$ 2,866	9,985	$ 5,520
Furniture and fixtures
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	4,086		4,086		4,614
Computer hardware and software
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	15,983		15,983		14,789
Leasehold improvements
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	2,971		2,971		2,410
Equipment under finance lease
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	2,247		2,247		1,957
Accumulated depreciation and amortization	(1,572)		(1,572)		(1,291)
Total equipment and leasehold improvements, net	675		675		666
Amortization			300		500
Automobiles, trucks, and field equipment
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	$ 3,255		$ 3,255		$ 3,564