EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 29, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Basic EPS
Net earnings attributable to Valmont Industries, Inc, basic	$ 54,868	$ 56,489	$ 89,563	$ 77,569	$ 65,036	$ 56,731	$ 59,980	$ 52,325	$ 278,489	$ 234,072	$ 228,308
Shares outstanding basic									26,641	26,471	26,329
Per share amount basic (in dollars per share)	$ 2.06	$ 2.12	$ 3.36	$ 2.92	$ 2.45	$ 2.14	$ 2.27	$ 1.98	$ 10.45	$ 8.84	$ 8.67
Dilutive Effect of Stock Options
Dilutive effect of stock options number of shares									258	293	221
Dilutive effect of stock options (in dollars per share)									$ 0.10	$ 0.09	$ 0.07
Diluted EPS
Net earnings attributable to Valmont Industries, Inc, diluted									$ 278,489	$ 234,072	$ 228,308
Shares outstanding dilutive									26,899	26,764	26,550
Per share amount diluted (in dollars per share)	$ 2.04	$ 2.10	$ 3.33	$ 2.89	$ 2.43	$ 2.12	$ 2.24	$ 1.96	$ 10.35	$ 8.75	$ 8.60
Antidilutive Securities
Outstanding stock options with exercise prices exceeding the market price of common stock, excluded from the computation of diluted earnings per share (in shares)									1,200	137,000	20,000