NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Assets (Details)	12 Months Ended
	Dec. 30, 2017 USD ($) item	Dec. 31, 2016 USD ($)
Amortizable intangible assets
Goodwill impairment charges recognized	$ 0	$ 0
Other long-term assets	$ 3,769,000	3,674,000
Number of aggregate property leases which require royalty payments to which the entity is a party | item	3
Recovery amount due pending outcome of litigation	$ 627,000
Aggregate property near Colorado Springs [Member]
Amortizable intangible assets
Other long-term assets		$ 2,500,000