GOODWILL AND INTANGIBLE ASSETS (Details 2) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Webforge
Non-amortized intangible assets
Carrying value of trade names	$ 16,997	$ 16,801
Valmont SM
Non-amortized intangible assets
Carrying value of trade names	9,294	10,818
Newmark
Non-amortized intangible assets
Carrying value of trade names	11,111	11,111
Ingal EPS/Ingal Civil Products
Non-amortized intangible assets
Carrying value of trade names	8,971	8,867
Donhad
Non-amortized intangible assets
Carrying value of trade names	6,767	6,689
Shakespeare Member
Non-amortized intangible assets
Carrying value of trade names	4,000	4,000
Industrial Galvanizers
Non-amortized intangible assets
Carrying value of trade names	3,935	3,889
Other
Non-amortized intangible assets
Carrying value of trade names	14,140	14,852
Trade names
Non-amortized intangible assets
Carrying value of trade names	$ 75,215	$ 77,027