GOODWILL AND INTANGIBLE ASSETS - Carrying Amount of Goodwill by Segment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 26, 2016	Dec. 26, 2015
Goodwill
Goodwill, Gross		$ 371,808
Carrying amount of goodwill
Balance at the beginning of the period	$ 336,916
Balance at December 26, 2015		(34,892)
Foreign currency translation	(2,647)
Balance at the end of the period	334,269	336,916
Engineered Support Structures Segment
Goodwill
Goodwill, Gross		101,275
Carrying amount of goodwill
Balance at the beginning of the period	101,275
Foreign currency translation	(1,502)
Balance at the end of the period	99,773	101,275
Energy and Mining Segment [Member]
Goodwill
Goodwill, Gross		99,829
Carrying amount of goodwill
Balance at the beginning of the period	81,159
Balance at December 26, 2015		(18,670)
Foreign currency translation	(1,462)
Balance at the end of the period	79,697	81,159
Utility Support Structures Segment
Goodwill
Goodwill, Gross		75,404
Carrying amount of goodwill
Balance at the beginning of the period	75,404
Foreign currency translation	0
Balance at the end of the period	75,404	75,404
Coatings Segment
Goodwill
Goodwill, Gross		75,941
Carrying amount of goodwill
Balance at the beginning of the period	59,719
Balance at December 26, 2015	(9,100)	(16,222)
Foreign currency translation	290
Balance at the end of the period	60,009	59,719
Irrigation Segment
Goodwill
Goodwill, Gross		19,359
Carrying amount of goodwill
Balance at the beginning of the period	19,359
Foreign currency translation	27
Balance at the end of the period	$ 19,386	$ 19,359