INDUSTRY SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Oct. 01, 2016 USD ($)	Jul. 02, 2016 USD ($)	Apr. 02, 2016 USD ($)	Jan. 02, 2016 USD ($)	Oct. 03, 2015 USD ($)	Jul. 04, 2015 USD ($)	Apr. 04, 2015 USD ($)	Dec. 31, 2016 USD ($) item	Jan. 02, 2016 USD ($)
INDUSTRY SEGMENT INFORMATION
Number of industry groups in which the entity operates | item									2
Revenues from external customers	$ 36,996	$ 37,647	$ 42,721	$ 34,228	$ 35,120	$ 36,165	$ 34,865	$ 30,685	$ 151,592	$ 136,835
Depreciation, depletion and amortization	539	$ 607	$ 651	$ 639	484	$ 640	$ 651	$ 646	2,436	2,421
Operating (loss) income									5,841	2,516
Segment assets	78,008				75,755				78,008	75,755
Capital expenditures									4,405	2,303
Concrete Aggregates and Construction Supplies [Member]
INDUSTRY SEGMENT INFORMATION
Revenues from external customers									67,091	55,319
Depreciation, depletion and amortization									1,340	1,364
Operating (loss) income									3,433	(256)
Segment assets	33,518				31,791				33,518	31,791
Capital expenditures									3,296	1,539
Doors [Member]
INDUSTRY SEGMENT INFORMATION
Revenues from external customers									16,990	16,981
Depreciation, depletion and amortization									134	128
Operating (loss) income									1,563	1,280
Segment assets	6,173				6,471				6,173	6,471
Capital expenditures									110	31
Heating and Cooling [Member]
INDUSTRY SEGMENT INFORMATION
Revenues from external customers									41,853	39,498
Depreciation, depletion and amortization									526	504
Operating (loss) income									3,046	3,371
Segment assets	22,381				22,628				22,381	22,628
Capital expenditures									655	494
Evaporative Cooling [Member]
INDUSTRY SEGMENT INFORMATION
Revenues from external customers									25,642	25,022
Depreciation, depletion and amortization									413	399
Operating (loss) income									1,413	1,135
Segment assets	12,283				12,730				12,283	12,730
Capital expenditures									182	239
Corporate, Non-Segment [Member]
INDUSTRY SEGMENT INFORMATION
Revenues from external customers									16	15
Depreciation, depletion and amortization									23	26
Operating (loss) income									(3,614)	(3,014)
Segment assets	3,653				2,135				3,653	2,135
Capital expenditures									$ 162
Construction Products [Member]
INDUSTRY SEGMENT INFORMATION
Number of reportable segments | item									2
Revenues from external customers									$ 84,081	72,300
Depreciation, depletion and amortization									1,474	1,492
Operating (loss) income									4,996	1,024
Segment assets	39,691				38,262				39,691	38,262
Capital expenditures									$ 3,406	1,570
Heating Ventilation and Air Conditioning Products [Member]
INDUSTRY SEGMENT INFORMATION
Number of reportable segments | item									2
Revenues from external customers									$ 67,495	64,520
Depreciation, depletion and amortization									939	903
Operating (loss) income									4,459	4,506
Segment assets	$ 34,664				$ 35,358				34,664	35,358
Capital expenditures									$ 837	$ 733