RESTRUCTURING ACTIVITIES (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 29, 2019 facility	Sep. 29, 2018 USD ($)	Dec. 29, 2018 USD ($) facility	Dec. 30, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Goodwill impairment		$ 14,355	$ 14,355	$ 34,892
Broad Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			$ 4,581
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Number Of Facilities Closed | facility			7
ESS | Restructuring Asset Impairment
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost			$ 8
Coatings Segment
Restructuring Cost and Reserve [Line Items]
Goodwill impairment			14,355	0
Engineered Support Structures
Restructuring Cost and Reserve [Line Items]
Goodwill impairment			0	18,670
Coatings
Restructuring Cost and Reserve [Line Items]
Goodwill impairment			0	16,222
Other
Restructuring Cost and Reserve [Line Items]
Goodwill impairment			0	0
Other
Restructuring Cost and Reserve [Line Items]
Goodwill impairment			0	$ 0
Selling, General and Administrative Expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			7,825
Selling, General and Administrative Expenses | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			585
Selling, General and Administrative Expenses | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			2,195
Selling, General and Administrative Expenses | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			2,780
Selling, General and Administrative Expenses | Engineered Support Structures | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			7,286
Selling, General and Administrative Expenses | Engineered Support Structures | Broad Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,040
Selling, General and Administrative Expenses | Engineered Support Structures | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			349
Selling, General and Administrative Expenses | Engineered Support Structures | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,961
Selling, General and Administrative Expenses | Engineered Support Structures | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			2,310
Selling, General and Administrative Expenses | Coatings | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			305
Selling, General and Administrative Expenses | Coatings | Broad Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			602
Selling, General and Administrative Expenses | Coatings | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			236
Selling, General and Administrative Expenses | Coatings | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Selling, General and Administrative Expenses | Coatings | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			236
Selling, General and Administrative Expenses | Other | Broad Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			468
Selling, General and Administrative Expenses | Other | Broad Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,943
Selling, General and Administrative Expenses | Other/ Corporate | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			234
Selling, General and Administrative Expenses | Other/ Corporate | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Selling, General and Administrative Expenses | Other/ Corporate | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			234
Selling, General and Administrative Expenses | Other/ Corporate | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			234
Cost of Sales | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			5,045
Cost of Sales | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,689
Cost of Sales | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			2,257
Cost of Sales | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,099
Cost of Sales | Coatings Segment | Broad Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			528
Cost of Sales | Engineered Support Structures | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			4,976
Cost of Sales | Engineered Support Structures | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,620
Cost of Sales | Engineered Support Structures | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			2,257
Cost of Sales | Engineered Support Structures | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			1,099
Cost of Sales | Coatings | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			69
Cost of Sales | Coatings | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			69
Cost of Sales | Coatings | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Cost of Sales | Coatings | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Cost of Sales | Other/ Corporate | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Cost of Sales | Other/ Corporate | Severance | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Cost of Sales | Other/ Corporate | Other cash restructuring expenses | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			0
Cost of Sales | Other/ Corporate | Asset impairments/net loss on disposals | 2016 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining			$ 0
CHINA | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Number Of Facilities Closed | facility			3
Scenario, Forecast | ESS | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Number Of Facilities Closed | facility	1
Scenario, Forecast | Utility Support Structures Segment | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Number Of Facilities Closed | facility	1