GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 29, 2012	Dec. 31, 2011	Dec. 25, 2010	Dec. 26, 2009
Current assets:
Cash and cash equivalents	$ 414,129	$ 362,894	$ 346,904	$ 180,786
Receivables, net	515,902	426,683
Inventories	412,384	393,782
Prepaid expenses	25,144	25,765
Refundable and deferred income taxes	58,381	43,819
Total current assets	1,425,940	1,252,943
Property, plant and equipment, at cost	994,774	911,642
Less accumulated depreciation and amortization	482,162	456,765
Net property, plant and equipment	512,612	454,877
Goodwill	330,791	314,662	314,847
Other intangible assets	172,270	168,083
Other assets	126,938	115,511
Total assets	2,568,551	2,306,076	2,090,743
Current liabilities:
Current installments of long-term debt	224	235
Notes payable to banks	13,375	11,403
Accounts payable	212,424	216,729
Accrued employee compensation and benefits	101,905	83,613
Accrued expenses	78,503	73,515
Income taxes payable		17,808
Dividends payable	6,002	4,767
Total current liabilities	412,433	408,070
Deferred income taxes	88,300	85,497	89,922
Long-term debt, excluding current installments	472,593	474,415
Defined benefit pension liability	112,043	68,024
Deferred compensation	31,920	30,741
Other noncurrent liabilities	44,252	41,418
Commitments and contingencies
Shareholders' equity:
Common stock of $1 par value	27,900	27,900
Common stock, par value (in dollars per share)	$ 1	$ 1
Retained earnings	1,300,529	1,079,698
Accumulated other comprehensive income	43,938	64,052
Treasury stock	(22,455)	(24,688)
Total Valmont Industries, Inc. shareholders' equity	1,349,912	1,146,962
Noncontrolling interest in consolidated subsidiaries	57,098	50,949
Total shareholders' equity	1,407,010	1,197,911	1,010,127	808,307
Total liabilities and shareholders' equity	2,568,551	2,306,076
Parent
Current assets:
Cash and cash equivalents	40,926	27,545	8,015	82,017
Receivables, net	144,161	122,409
Inventories	146,619	125,862
Prepaid expenses	7,153	3,448
Refundable and deferred income taxes	29,359	22,053
Total current assets	368,218	301,317
Property, plant and equipment, at cost	456,497	427,398
Less accumulated depreciation and amortization	288,226	283,786
Net property, plant and equipment	168,271	143,612
Goodwill	20,108	20,108
Other intangible assets	499	661
Investment in subsidiaries and intercompany accounts	1,456,159	1,338,299
Other assets	32,511	30,192
Total assets	2,045,766	1,834,189
Current liabilities:
Current installments of long-term debt	189	187
Accounts payable	72,610	68,166
Accrued employee compensation and benefits	61,572	44,187
Accrued expenses	30,641	28,154
Income taxes payable		17,808
Dividends payable	6,002	4,767
Total current liabilities	171,014	163,269
Deferred income taxes	23,305	21,891
Long-term debt, excluding current installments	471,828	473,419
Deferred compensation	25,200	24,142
Other noncurrent liabilities	4,507	4,506
Shareholders' equity:
Common stock of $1 par value	27,900	27,900
Retained earnings	1,300,529	1,079,698
Accumulated other comprehensive income	43,938	64,052
Treasury stock	(22,455)	(24,688)
Total Valmont Industries, Inc. shareholders' equity	1,349,912	1,146,962
Total shareholders' equity	1,349,912	1,146,962
Total liabilities and shareholders' equity	2,045,766	1,834,189
Guarantors
Current assets:
Cash and cash equivalents	83,203	18,257	619	1,666
Receivables, net	86,403	53,567
Inventories	71,988	77,838
Prepaid expenses	1,029	1,009
Refundable and deferred income taxes	6,904	6,218
Total current assets	249,527	156,889
Property, plant and equipment, at cost	122,937	107,315
Less accumulated depreciation and amortization	55,239	54,740
Net property, plant and equipment	67,698	52,575
Goodwill	107,542	107,542
Other intangible assets	53,517	59,389
Investment in subsidiaries and intercompany accounts	1,246,777	695,745
Total assets	1,725,061	1,072,140
Current liabilities:
Accounts payable	22,006	21,428
Accrued employee compensation and benefits	10,530	8,608
Accrued expenses	4,674	5,651
Income taxes payable	31
Total current liabilities	37,241	35,687
Deferred income taxes	27,851	27,661
Long-term debt, excluding current installments	599,873
Shareholders' equity:
Common stock of $1 par value	457,950	457,950
Additional paid-in capital	150,286	181,542
Retained earnings	467,240	370,258
Accumulated other comprehensive income	(15,380)	(958)
Total Valmont Industries, Inc. shareholders' equity	1,060,096	1,008,792
Total shareholders' equity	1,060,096	1,008,792
Total liabilities and shareholders' equity	1,725,061	1,072,140
Non-Guarantors
Current assets:
Cash and cash equivalents	290,000	317,092	338,270	97,103
Receivables, net	285,338	250,707
Inventories	193,777	190,082
Prepaid expenses	16,962	21,308
Refundable and deferred income taxes	22,118	15,548
Total current assets	808,195	794,737
Property, plant and equipment, at cost	415,340	376,929
Less accumulated depreciation and amortization	138,697	118,239
Net property, plant and equipment	276,643	258,690
Goodwill	203,141	187,012
Other intangible assets	118,254	108,033
Investment in subsidiaries and intercompany accounts	615,152	596,301
Other assets	94,427	85,319
Total assets	2,115,812	2,030,092
Current liabilities:
Current installments of long-term debt	35	48
Notes payable to banks	13,375	11,403
Accounts payable	117,808	127,135
Accrued employee compensation and benefits	29,803	30,818
Accrued expenses	43,188	39,710
Income taxes payable	669
Total current liabilities	204,878	209,114
Deferred income taxes	37,144	35,945
Long-term debt, excluding current installments	765	996
Defined benefit pension liability	112,043	68,024
Deferred compensation	6,720	6,599
Other noncurrent liabilities	39,745	36,912
Shareholders' equity:
Common stock of $1 par value	254,982	254,982
Additional paid-in capital	893,274	893,884
Retained earnings	443,337	407,677
Accumulated other comprehensive income	65,826	65,010
Total Valmont Industries, Inc. shareholders' equity	1,657,419	1,621,553
Noncontrolling interest in consolidated subsidiaries	57,098	50,949
Total shareholders' equity	1,714,517	1,672,502
Total liabilities and shareholders' equity	2,115,812	2,030,092
Eliminations
Current assets:
Investment in subsidiaries and intercompany accounts	(3,318,088)	(2,630,345)
Total assets	(3,318,088)	(2,630,345)
Current liabilities:
Income taxes payable	(700)
Total current liabilities	(700)
Long-term debt, excluding current installments	(599,873)
Shareholders' equity:
Common stock of $1 par value	(712,932)	(712,932)
Additional paid-in capital	(1,043,560)	(1,075,426)
Retained earnings	(910,577)	(777,935)
Accumulated other comprehensive income	(50,446)	(64,052)
Total Valmont Industries, Inc. shareholders' equity	(2,717,515)	(2,630,345)
Total shareholders' equity	(2,717,515)	(2,630,345)
Total liabilities and shareholders' equity	$ (3,318,088)	$ (2,630,345)