GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 4) (USD $) In Thousands, unless otherwise specified	Mar. 28, 2015	Dec. 27, 2014	Mar. 29, 2014	Dec. 28, 2013
Current assets:
Cash and cash equivalents	$ 318,366	$ 371,579	$ 488,195	$ 613,706
Receivables, net	503,649	536,918
Inventories	379,514	359,522
Prepaid expenses	48,344	56,912
Refundable and deferred income taxes	53,032	68,010
Total current assets	1,302,905	1,392,941
Property, plant and equipment, at cost	1,124,251	1,139,569
Less accumulated depreciation and amortization	537,505	533,116
Net property, plant and equipment	586,746	606,453
Goodwill	373,888	385,111
Other intangible assets	189,390	202,004
Other assets	131,201	143,159
Total assets	2,584,130	2,729,668
Current liabilities:
Current installments of long-term debt	1,070	1,181
Notes payable to banks	14,459	13,952
Accounts payable	189,349	196,565
Accrued employee compensation and benefits	71,188	87,950
Accrued expenses	98,636	88,480
Dividends payable	8,889	9,086
Total current liabilities	383,591	397,214
Deferred income taxes	66,329	71,797
Long-term debt, excluding current installments	765,762	766,654
Defined benefit pension liability	127,708	150,124
Deferred compensation	51,027	47,932
Other noncurrent liabilities	45,849	45,542
Shareholders' equity:
Common stock of $1 par value	27,900	27,900
Retained earnings	1,741,252	1,718,662
Accumulated other comprehensive income	(190,204)	(134,433)
Treasury stock	(481,039)	(410,296)
Total Valmont Industries, Inc. shareholders' equity	1,097,909	1,201,833
Noncontrolling interest in consolidated subsidiaries	45,955	48,572
Total shareholders' equity	1,143,864	1,250,405	1,619,803	1,544,846
Total liabilities and shareholders' equity	2,584,130	2,729,668
Parent
Current assets:
Cash and cash equivalents	25,571	69,869	81,941	215,576
Receivables, net	163,095	158,316
Inventories	122,962	127,859
Prepaid expenses	4,806	7,087
Refundable and deferred income taxes	39,909	53,307
Total current assets	356,343	416,438
Property, plant and equipment, at cost	561,174	556,658
Less accumulated depreciation and amortization	326,839	319,899
Net property, plant and equipment	234,335	236,759
Goodwill	20,108	20,108
Other intangible assets	279	292
Investment in subsidiaries and intercompany accounts	1,405,751	1,446,989
Other assets	49,615	46,587
Total assets	2,066,431	2,167,173
Current liabilities:
Current installments of long-term debt	213	213
Accounts payable	64,251	59,893
Accrued employee compensation and benefits	32,270	48,169
Accrued expenses	44,316	32,616
Dividends payable	8,889	9,086
Total current liabilities	149,939	149,977
Deferred income taxes	3,906	5,584
Long-term debt, excluding current installments	759,682	759,895
Deferred compensation	45,121	41,803
Other noncurrent liabilities	9,874	8,081
Shareholders' equity:
Common stock of $1 par value	27,900	27,900
Retained earnings	1,741,252	1,718,662
Accumulated other comprehensive income	(190,204)	(134,433)
Treasury stock	(481,039)	(410,296)
Total Valmont Industries, Inc. shareholders' equity	1,097,909	1,201,833
Total shareholders' equity	1,097,909	1,201,833
Total liabilities and shareholders' equity	2,066,431	2,167,173
Guarantors
Current assets:
Cash and cash equivalents	1,367	2,157	26,608	29,797
Receivables, net	61,818	68,414
Inventories	65,221	54,914
Prepaid expenses	753	502
Refundable and deferred income taxes	6,397	6,194
Total current assets	135,556	132,181
Property, plant and equipment, at cost	125,618	124,182
Less accumulated depreciation and amortization	67,383	65,493
Net property, plant and equipment	58,235	58,689
Goodwill	107,542	107,542
Other intangible assets	42,439	43,644
Investment in subsidiaries and intercompany accounts	821,802	825,236
Total assets	1,165,574	1,167,292
Current liabilities:
Accounts payable	13,709	15,151
Accrued employee compensation and benefits	4,359	5,385
Accrued expenses	6,077	6,052
Total current liabilities	24,145	26,588
Deferred income taxes	28,658	28,988
Shareholders' equity:
Common stock of $1 par value	457,950	457,950
Additional paid-in capital	150,286	150,286
Retained earnings	562,619	552,676
Accumulated other comprehensive income	(58,084)	(49,196)
Total Valmont Industries, Inc. shareholders' equity	1,112,771	1,111,716
Total shareholders' equity	1,112,771	1,111,716
Total liabilities and shareholders' equity	1,165,574	1,167,292
Non-Guarantors
Current assets:
Cash and cash equivalents	291,428	299,553	379,646	368,333
Receivables, net	278,736	310,188
Inventories	194,400	177,512
Prepaid expenses	42,785	49,323
Refundable and deferred income taxes	6,726	8,509
Total current assets	814,075	845,085
Property, plant and equipment, at cost	437,459	458,729
Less accumulated depreciation and amortization	143,283	147,724
Net property, plant and equipment	294,176	311,005
Goodwill	246,238	257,461
Other intangible assets	146,672	158,068
Investment in subsidiaries and intercompany accounts	896,850	887,055
Other assets	81,586	96,572
Total assets	2,479,597	2,555,246
Current liabilities:
Current installments of long-term debt	857	968
Notes payable to banks	14,459	13,952
Accounts payable	111,389	121,521
Accrued employee compensation and benefits	34,559	34,396
Accrued expenses	48,243	49,812
Total current liabilities	209,507	220,649
Deferred income taxes	33,765	37,225
Long-term debt, excluding current installments	6,080	6,759
Defined benefit pension liability	127,708	150,124
Deferred compensation	5,906	6,129
Other noncurrent liabilities	35,975	37,461
Shareholders' equity:
Common stock of $1 par value	648,682	648,682
Additional paid-in capital	1,098,408	1,098,408
Retained earnings	409,583	397,302
Accumulated other comprehensive income	(141,972)	(96,065)
Total Valmont Industries, Inc. shareholders' equity	2,014,701	2,048,327
Noncontrolling interest in consolidated subsidiaries	45,955	48,572
Total shareholders' equity	2,060,656	2,096,899
Total liabilities and shareholders' equity	2,479,597	2,555,246
Eliminations
Current assets:
Inventories	(3,069)	(763)
Total current assets	(3,069)	(763)
Investment in subsidiaries and intercompany accounts	(3,124,403)	(3,159,280)
Total assets	(3,127,472)	(3,160,043)
Shareholders' equity:
Common stock of $1 par value	(1,106,632)	(1,106,632)
Additional paid-in capital	(1,248,694)	(1,248,694)
Retained earnings	(972,202)	(949,978)
Accumulated other comprehensive income	200,056	145,261
Total Valmont Industries, Inc. shareholders' equity	(3,127,472)	(3,160,043)
Total shareholders' equity	(3,127,472)	(3,160,043)
Total liabilities and shareholders' equity	$ (3,127,472)	$ (3,160,043)