SUPPLEMENTAL FINANCIAL STATEMENT DATA - Equipment And Leasehold Improvements, Net (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Apr. 03, 2020	Mar. 29, 2019	Dec. 27, 2019
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	$ 27,627		$ 27,334
Accumulated depreciation and amortization	(14,490)		(15,283)
Total equipment and leasehold improvements, net	13,137		12,051
Amortization	4,519	$ 2,654
Furniture and fixtures
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	4,071		4,614
Computer hardware and software
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	15,318		14,789
Leasehold improvements
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	2,872		2,410
Equipment under finance lease
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	2,122		1,957
Accumulated depreciation and amortization	(1,418)		(1,291)
Total equipment and leasehold improvements, net	704		666
Amortization	200		500
Automobiles, trucks, and field equipment
EQUIPMENT AND LEASEHOLD IMPROVEMENTS
Equipment and leasehold improvements, gross	$ 3,244		$ 3,564

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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