GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION (Details 3) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014	Sep. 27, 2014	Dec. 28, 2013
Current assets:
Cash and cash equivalents	$ 399,948	$ 349,074	$ 371,579	$ 349,074	$ 613,706
Receivables, less allowance of $10,250 in 2016 and $10,055 in 2015	439,342	466,443
Inventories	350,028	340,672
Prepaid expenses, restricted cash, and other assets	57,297	46,137
Refundable income taxes	6,601	24,526
Total current assets	1,253,216	1,226,852
Property, plant and equipment, at cost	1,105,736	1,081,056
Less accumulated depreciation and amortization	587,401	548,567
Net property, plant and equipment	518,335	532,489
Goodwill	321,110	336,916	385,111
Other intangible assets	144,378	170,197
Investment in subsidiaries and intercompany accounts	0	0
Other assets, less allowance for doubtful receivables of $8,741 in 2016 and $10,953 in 2015	154,692	125,928
Total assets	2,391,731	2,392,382	2,721,955
Current liabilities:
Current installments of long-term debt	851	1,077
Notes payable to banks	746	976
Accounts payable	177,488	179,983
Accrued employee compensation and benefits	72,404	70,354
Accrued expenses	89,914	105,593
Dividends payable	8,445	8,571
Total current liabilities	(349,848)	(366,554)
Deferred income taxes	35,803	35,669
Long-term debt, excluding current installments	754,795	756,918
Defined benefit pension liability	209,470	179,323
Deferred compensation	44,319	48,417
Other noncurrent liabilities	14,910	40,290
Shareholders’ equity:
Common stock of $1 par value	27,900	27,900
Additional paid-in capital	0	0
Retained earnings	1,874,722	1,729,679
Accumulated other comprehensive income (loss)	(346,359)	(267,218)
Cost of treasury stock, common shares of 5,379,106 in 2016 and 5,042,775 in 2015	(612,781)	(571,920)
Total Valmont Industries, Inc. shareholders’ equity	943,482	918,441
Noncontrolling interest in consolidated subsidiaries	39,104	46,770
Total shareholders’ equity	982,586	965,211	1,250,405		1,544,846
Total liabilities and shareholders’ equity	2,391,731	2,392,382
Eliminations
Current assets:
Cash and cash equivalents	0	0	0		0
Receivables, less allowance of $10,250 in 2016 and $10,055 in 2015	0	0
Inventories	(4,154)	(2,993)
Prepaid expenses, restricted cash, and other assets	0	0
Refundable income taxes	0	0
Total current assets	(4,154)	(2,993)
Property, plant and equipment, at cost	0	0
Less accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Goodwill	0	0
Other intangible assets	0	0
Investment in subsidiaries and intercompany accounts	(3,270,540)	(2,992,184)
Other assets, less allowance for doubtful receivables of $8,741 in 2016 and $10,953 in 2015	0	0
Total assets	(3,274,694)	(2,995,177)
Current liabilities:
Current installments of long-term debt	0	0
Notes payable to banks	0	0
Accounts payable	0	0
Accrued employee compensation and benefits	0	0
Accrued expenses	0	0
Dividends payable	0	0
Total current liabilities	0	0
Deferred income taxes	0	0
Long-term debt, excluding current installments	0	0
Defined benefit pension liability	0	0
Deferred compensation	0	0
Other noncurrent liabilities	0	0
Shareholders’ equity:
Common stock of $1 par value	(1,106,633)	(1,106,633)
Additional paid-in capital	(1,266,950)	(1,266,950)
Retained earnings	(1,250,087)	(896,644)
Accumulated other comprehensive income (loss)	348,976	275,050
Cost of treasury stock, common shares of 5,379,106 in 2016 and 5,042,775 in 2015	0	0
Total Valmont Industries, Inc. shareholders’ equity	(3,274,694)	(2,995,177)
Noncontrolling interest in consolidated subsidiaries	0	0
Total shareholders’ equity	(3,274,694)	(2,995,177)
Total liabilities and shareholders’ equity	(3,274,694)	(2,995,177)
Parent
Current assets:
Cash and cash equivalents	67,225	62,281	69,869		215,576
Receivables, less allowance of $10,250 in 2016 and $10,055 in 2015	134,351	130,741
Inventories	126,669	132,222
Prepaid expenses, restricted cash, and other assets	13,271	9,900
Refundable income taxes	6,601	24,526
Total current assets	348,117	359,670
Property, plant and equipment, at cost	547,076	541,536
Less accumulated depreciation and amortization	352,960	334,471
Net property, plant and equipment	194,116	207,065
Goodwill	20,108	20,108
Other intangible assets	184	238
Investment in subsidiaries and intercompany accounts	1,279,413	1,239,228
Other assets, less allowance for doubtful receivables of $8,741 in 2016 and $10,953 in 2015	43,880	40,067
Total assets	1,885,818	1,866,376
Current liabilities:
Current installments of long-term debt	0	215
Notes payable to banks	0	0
Accounts payable	52,272	66,723
Accrued employee compensation and benefits	34,508	32,272
Accrued expenses	30,261	31,073
Dividends payable	8,445	8,571
Total current liabilities	(125,486)	(138,854)
Deferred income taxes	22,481	9,686
Long-term debt, excluding current installments	751,251	751,765
Defined benefit pension liability	0	0
Deferred compensation	39,476	43,485
Other noncurrent liabilities	3,642	4,145
Shareholders’ equity:
Common stock of $1 par value	27,900	27,900
Additional paid-in capital	0	0
Retained earnings	1,874,722	1,729,679
Accumulated other comprehensive income (loss)	(346,359)	(267,218)
Cost of treasury stock, common shares of 5,379,106 in 2016 and 5,042,775 in 2015	(612,781)	(571,920)
Total Valmont Industries, Inc. shareholders’ equity	943,482	918,441
Noncontrolling interest in consolidated subsidiaries	0	0
Total shareholders’ equity	943,482	918,441
Total liabilities and shareholders’ equity	1,885,818	1,866,376
Guarantors
Current assets:
Cash and cash equivalents	6,071	4,008	2,157		29,797
Receivables, less allowance of $10,250 in 2016 and $10,055 in 2015	60,522	66,387
Inventories	45,457	38,379
Prepaid expenses, restricted cash, and other assets	880	766
Refundable income taxes	0	0
Total current assets	112,930	109,540
Property, plant and equipment, at cost	153,596	132,864
Less accumulated depreciation and amortization	76,776	69,956
Net property, plant and equipment	76,820	62,908
Goodwill	110,561	110,562
Other intangible assets	35,953	40,959
Investment in subsidiaries and intercompany accounts	901,758	813,779
Other assets, less allowance for doubtful receivables of $8,741 in 2016 and $10,953 in 2015	0	0
Total assets	1,238,022	1,137,748
Current liabilities:
Current installments of long-term debt	0	0
Notes payable to banks	0	0
Accounts payable	15,732	13,680
Accrued employee compensation and benefits	7,243	6,347
Accrued expenses	15,242	22,802
Dividends payable	0	0
Total current liabilities	(38,217)	(42,829)
Deferred income taxes	0	0
Long-term debt, excluding current installments	0	0
Defined benefit pension liability	0	0
Deferred compensation	0	0
Other noncurrent liabilities	5	0
Shareholders’ equity:
Common stock of $1 par value	457,950	457,950
Additional paid-in capital	159,414	159,414
Retained earnings	646,749	541,917
Accumulated other comprehensive income (loss)	(64,313)	(64,362)
Cost of treasury stock, common shares of 5,379,106 in 2016 and 5,042,775 in 2015	0	0
Total Valmont Industries, Inc. shareholders’ equity	1,199,800	1,094,919
Noncontrolling interest in consolidated subsidiaries	0	0
Total shareholders’ equity	1,199,800	1,094,919
Total liabilities and shareholders’ equity	1,238,022	1,137,748
Non- Guarantors
Current assets:
Cash and cash equivalents	326,652	282,785	$ 299,553		$ 368,333
Receivables, less allowance of $10,250 in 2016 and $10,055 in 2015	244,469	269,315
Inventories	182,056	173,064
Prepaid expenses, restricted cash, and other assets	43,146	35,471
Refundable income taxes	0	0
Total current assets	796,323	760,635
Property, plant and equipment, at cost	405,064	406,656
Less accumulated depreciation and amortization	157,665	144,140
Net property, plant and equipment	247,399	262,516
Goodwill	190,441	206,246
Other intangible assets	108,241	129,000
Investment in subsidiaries and intercompany accounts	1,089,369	939,177
Other assets, less allowance for doubtful receivables of $8,741 in 2016 and $10,953 in 2015	110,812	85,861
Total assets	2,542,585	2,383,435
Current liabilities:
Current installments of long-term debt	851	862
Notes payable to banks	746	976
Accounts payable	109,484	99,580
Accrued employee compensation and benefits	30,653	31,735
Accrued expenses	44,411	51,718
Dividends payable	0	0
Total current liabilities	(186,145)	(184,871)
Deferred income taxes	13,322	25,983
Long-term debt, excluding current installments	3,544	5,153
Defined benefit pension liability	209,470	179,323
Deferred compensation	4,843	4,932
Other noncurrent liabilities	11,263	36,145
Shareholders’ equity:
Common stock of $1 par value	648,683	648,683
Additional paid-in capital	1,107,536	1,107,536
Retained earnings	603,338	354,727
Accumulated other comprehensive income (loss)	(284,663)	(210,688)
Cost of treasury stock, common shares of 5,379,106 in 2016 and 5,042,775 in 2015	0	0
Total Valmont Industries, Inc. shareholders’ equity	2,074,894	1,900,258
Noncontrolling interest in consolidated subsidiaries	39,104	46,770
Total shareholders’ equity	2,113,998	1,947,028
Total liabilities and shareholders’ equity	$ 2,542,585	$ 2,383,435