GUARANTOR/NON-GUARANTOR FINANCIAL INFORMATION - Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 25, 2016	Dec. 26, 2015	Jun. 27, 2015	Dec. 27, 2014
Current assets:
Cash and cash equivalents	$ 344,346	$ 349,074	$ 317,523	$ 371,579
Receivables, net	466,749	466,443
Inventories	372,106	340,672
Prepaid expenses, restricted cash, and other assets	63,650	46,137
Refundable income taxes	20,441	24,526
Total current assets	1,267,292	1,226,852
Property, plant and equipment, at cost	1,105,955	1,081,056
Less accumulated depreciation and amortization	579,608	548,567
Net property, plant and equipment	526,347	532,489
Goodwill	331,603	336,916
Other intangible assets	158,814	170,197
Investment in subsidiaries and intercompany accounts	0	0
Other assets	111,817	125,928
Total assets	2,395,873	2,392,382
Current liabilities:
Current installments of long-term debt	889	1,077
Notes payable to banks	3,735	976
Accounts payable	183,126	179,983
Accrued employee compensation and benefits	66,626	70,354
Accrued expenses	95,158	105,593
Dividends payable	8,505	8,571
Total current liabilities	(358,039)	(366,554)
Deferred income taxes	35,541	35,669
Long-term debt, excluding current installments	756,543	756,918
Defined benefit pension liability	164,329	179,323
Deferred compensation	48,965	48,417
Other noncurrent liabilities	38,285	40,290
Shareholders’ equity:
Common stock of $1 par value	27,900	27,900
Additional paid-in capital	0	0
Retained earnings	1,790,120	1,729,679
Accumulated other comprehensive loss	(268,459)	(267,218)
Treasury stock	(593,479)	(571,920)
Total Valmont Industries, Inc. shareholders’ equity	956,082	918,441
Noncontrolling interest in consolidated subsidiaries	38,089	46,770
Total shareholders’ equity	994,171	965,211	1,140,593	1,250,405
Total liabilities and shareholders’ equity	2,395,873	2,392,382
Parent
Current assets:
Cash and cash equivalents	62,149	62,281	12,453	69,869
Receivables, net	130,354	130,741
Inventories	140,981	132,222
Prepaid expenses, restricted cash, and other assets	11,405	9,900
Refundable income taxes	20,441	24,526
Total current assets	365,330	359,670
Property, plant and equipment, at cost	540,415	541,536
Less accumulated depreciation and amortization	345,295	334,471
Net property, plant and equipment	195,120	207,065
Goodwill	20,108	20,108
Other intangible assets	211	238
Investment in subsidiaries and intercompany accounts	1,268,543	1,239,228
Other assets	40,034	40,067
Total assets	1,889,346	1,866,376
Current liabilities:
Current installments of long-term debt	0	215
Notes payable to banks	0	0
Accounts payable	53,254	66,723
Accrued employee compensation and benefits	26,945	32,272
Accrued expenses	31,118	31,073
Dividends payable	8,505	8,571
Total current liabilities	(119,822)	(138,854)
Deferred income taxes	13,173	9,686
Long-term debt, excluding current installments	751,448	751,765
Defined benefit pension liability	0	0
Deferred compensation	43,887	43,485
Other noncurrent liabilities	4,934	4,145
Shareholders’ equity:
Common stock of $1 par value	27,900	27,900
Additional paid-in capital	0	0
Retained earnings	1,790,120	1,729,679
Accumulated other comprehensive loss	(268,459)	(267,218)
Treasury stock	(593,479)	(571,920)
Total Valmont Industries, Inc. shareholders’ equity	956,082	918,441
Noncontrolling interest in consolidated subsidiaries	0	0
Total shareholders’ equity	956,082	918,441
Total liabilities and shareholders’ equity	1,889,346	1,866,376
Guarantors
Current assets:
Cash and cash equivalents	4,022	4,008	1,800	2,157
Receivables, net	58,203	66,387
Inventories	38,542	38,379
Prepaid expenses, restricted cash, and other assets	730	766
Refundable income taxes	0	0
Total current assets	101,497	109,540
Property, plant and equipment, at cost	145,857	132,864
Less accumulated depreciation and amortization	74,076	69,956
Net property, plant and equipment	71,781	62,908
Goodwill	110,562	110,562
Other intangible assets	38,460	40,959
Investment in subsidiaries and intercompany accounts	852,048	813,779
Other assets	3	0
Total assets	1,174,351	1,137,748
Current liabilities:
Current installments of long-term debt	0	0
Notes payable to banks	0	0
Accounts payable	13,601	13,680
Accrued employee compensation and benefits	5,919	6,347
Accrued expenses	17,073	22,802
Dividends payable	0	0
Total current liabilities	(36,593)	(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	584,900	541,917
Accumulated other comprehensive loss	(64,511)	(64,362)
Treasury stock	0	0
Total Valmont Industries, Inc. shareholders’ equity	1,137,753	1,094,919
Noncontrolling interest in consolidated subsidiaries	0	0
Total shareholders’ equity	1,137,753	1,094,919
Total liabilities and shareholders’ equity	1,174,351	1,137,748
Non- Guarantors
Current assets:
Cash and cash equivalents	278,175	282,785	303,270	299,553
Receivables, net	278,192	269,315
Inventories	197,137	173,064
Prepaid expenses, restricted cash, and other assets	51,515	35,471
Refundable income taxes	0	0
Total current assets	805,019	760,635
Property, plant and equipment, at cost	419,683	406,656
Less accumulated depreciation and amortization	160,237	144,140
Net property, plant and equipment	259,446	262,516
Goodwill	200,933	206,246
Other intangible assets	120,143	129,000
Investment in subsidiaries and intercompany accounts	1,090,615	939,177
Other assets	71,780	85,861
Total assets	2,547,936	2,383,435
Current liabilities:
Current installments of long-term debt	889	862
Notes payable to banks	3,735	976
Accounts payable	116,271	99,580
Accrued employee compensation and benefits	33,762	31,735
Accrued expenses	46,967	51,718
Dividends payable	0	0
Total current liabilities	(201,624)	(184,871)
Deferred income taxes	22,368	25,983
Long-term debt, excluding current installments	5,095	5,153
Defined benefit pension liability	164,329	179,323
Deferred compensation	5,078	4,932
Other noncurrent liabilities	33,346	36,145
Shareholders’ equity:
Common stock of $1 par value	648,682	648,683
Additional paid-in capital	1,107,536	1,107,536
Retained earnings	530,930	354,727
Accumulated other comprehensive loss	(209,141)	(210,688)
Treasury stock	0	0
Total Valmont Industries, Inc. shareholders’ equity	2,078,007	1,900,258
Noncontrolling interest in consolidated subsidiaries	38,089	46,770
Total shareholders’ equity	2,116,096	1,947,028
Total liabilities and shareholders’ equity	2,547,936	2,383,435
Eliminations
Current assets:
Cash and cash equivalents	0	0	$ 0	$ 0
Receivables, net	0	0
Inventories	(4,554)	(2,993)
Prepaid expenses, restricted cash, and other assets	0	0
Refundable income taxes	0	0
Total current assets	(4,554)	(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	(3,211,206)	(2,992,184)
Other assets	0	0
Total assets	(3,215,760)	(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	(1,106,632)	(1,106,633)
Additional paid-in capital	(1,266,950)	(1,266,950)
Retained earnings	(1,115,830)	(896,644)
Accumulated other comprehensive loss	273,652	275,050
Treasury stock	0	0
Total Valmont Industries, Inc. shareholders’ equity	(3,215,760)	(2,995,177)
Noncontrolling interest in consolidated subsidiaries	0	0
Total shareholders’ equity	(3,215,760)	(2,995,177)
Total liabilities and shareholders’ equity	$ (3,215,760)	$ (2,995,177)