GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 29, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 24, 2011	Jun. 25, 2011	Mar. 26, 2011	Dec. 29, 2012	Dec. 31, 2011	Dec. 25, 2010
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net sales	$ 815,037	$ 729,839	$ 767,315	$ 717,350	$ 752,730	$ 672,192	$ 668,609	$ 567,949	$ 3,029,541	$ 2,661,480	$ 1,975,505
Cost of sales									2,227,085	1,994,670	1,455,931
Gross profit	224,345	192,402	199,395	186,314	194,945	167,390	167,982	136,493	802,456	666,810	519,574
Selling, general and administrative expenses									420,160	403,500	341,161
Operating income									382,296	263,310	178,413
Other income (expenses):
Interest expense									(31,625)	(36,175)	(30,947)
Interest income									8,272	9,265	4,840
Other									347	(2,643)	676
Total other income (expenses)									(23,006)	(29,553)	(25,431)
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries									359,290	233,757	152,982
Income tax expense (benefit):
Current									122,782	89,552	49,991
Deferred									3,720	(84,962)	5,017
Total income tax expense (benefit)									126,502	4,590	55,008
Earnings before equity in earnings of nonconsolidated subsidiaries									232,788	229,167	97,974
Equity in earnings of nonconsolidated subsidiaries									6,128	8,059	2,439
Net earnings									238,916	237,226	100,413
Less: Earnings attributable to noncontrolling interests									(4,844)	(8,918)	(6,034)
Net earnings attributable to Valmont Industries, Inc.	65,036	56,731	59,980	52,325	114,731	42,141	45,827	25,609	234,072	228,308	94,379
Parent
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net sales									1,375,238	1,164,400	847,396
Cost of sales									1,008,087	863,269	622,018
Gross profit									367,151	301,131	225,378
Selling, general and administrative expenses									178,669	166,964	147,054
Operating income									188,482	134,167	78,324
Other income (expenses):
Interest expense									(31,121)	(35,456)	(30,282)
Interest income									45	59	127
Other									1,938	(311)	995
Total other income (expenses)									(29,138)	(35,708)	(29,160)
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries									159,344	98,459	49,164
Income tax expense (benefit):
Current									59,648	48,243	19,525
Deferred									(4,721)	(4,787)	722
Total income tax expense (benefit)									54,927	43,456	20,247
Earnings before equity in earnings of nonconsolidated subsidiaries									104,417	55,003	28,917
Equity in earnings of nonconsolidated subsidiaries									129,655	173,305	65,462
Net earnings									234,072	228,308	94,379
Net earnings attributable to Valmont Industries, Inc.									234,072	228,308	94,379
Guarantors
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net sales									620,338	401,443	304,309
Cost of sales									489,560	323,812	231,696
Gross profit									130,778	77,631	72,613
Selling, general and administrative expenses									55,488	50,783	47,688
Operating income									75,290	26,848	24,925
Other income (expenses):
Interest expense									(49,762)		(1)
Interest income									1,131	331	31
Other									55	59	(48)
Total other income (expenses)									(48,576)	390	(18)
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries									26,714	27,238	24,907
Income tax expense (benefit):
Current									16,398	10,571	5,039
Deferred									(496)	(964)	4,984
Total income tax expense (benefit)									15,902	9,607	10,023
Earnings before equity in earnings of nonconsolidated subsidiaries									10,812	17,631	14,884
Equity in earnings of nonconsolidated subsidiaries									86,170	125,269	25,264
Net earnings									96,982	142,900	40,148
Net earnings attributable to Valmont Industries, Inc.									96,982	142,900	40,148
Non-Guarantors
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net sales									1,331,827	1,305,424	956,023
Cost of sales									1,026,037	1,016,305	735,195
Gross profit									305,790	289,119	220,828
Selling, general and administrative expenses									186,003	185,753	146,419
Operating income									119,787	103,366	74,409
Other income (expenses):
Interest expense									(504)	(719)	(664)
Interest income									56,858	8,875	4,682
Other									(1,646)	(2,391)	(271)
Total other income (expenses)									54,708	5,765	3,747
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries									174,495	109,131	78,156
Income tax expense (benefit):
Current									47,375	30,738	25,427
Deferred									8,937	(79,211)	(689)
Total income tax expense (benefit)									56,312	(48,473)	24,738
Earnings before equity in earnings of nonconsolidated subsidiaries									118,183	157,604	53,418
Equity in earnings of nonconsolidated subsidiaries									5,150	6,818	1,525
Net earnings									123,333	164,422	54,943
Less: Earnings attributable to noncontrolling interests									(4,844)	(8,918)	(6,034)
Net earnings attributable to Valmont Industries, Inc.									118,489	155,504	48,909
Eliminations
Condensed consolidated financial information for the Company (Parent), the guarantor subsidiaries and the non-guarantor subsidiaries
Net sales									(297,862)	(209,787)	(132,223)
Cost of sales									(296,599)	(208,716)	(132,978)
Gross profit									(1,263)	(1,071)	755
Operating income									(1,263)	(1,071)	755
Other income (expenses):
Interest expense									49,762
Interest income									(49,762)
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries									(1,263)	(1,071)	755
Income tax expense (benefit):
Current									(639)
Total income tax expense (benefit)									(639)
Earnings before equity in earnings of nonconsolidated subsidiaries									(624)	(1,071)	755
Equity in earnings of nonconsolidated subsidiaries									(214,847)	(297,333)	(89,812)
Net earnings									(215,471)	(298,404)	(89,057)
Net earnings attributable to Valmont Industries, Inc.									$ (215,471)	$ (298,404)	$ (89,057)