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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020	Dec. 26, 2020
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 774,886	$ 674,200
Contract assets	117,539		$ 123,495
Contract liabilties	194,427		170,919
Contract liabilities, current	150,068		$ 130,018
Revenue recognized from contract liability	38,102	18,240
Remaining performance obligations	$ 44,359
Minimum
Disaggregation of Revenue [Line Items]
Remaining performance obligations, expected timing of satisfaction period	12 months
Maximum
Disaggregation of Revenue [Line Items]
Remaining performance obligations, expected timing of satisfaction period	24 months
Contract Liabilities
Disaggregation of Revenue [Line Items]
Contract liabilities, current	$ 150,068
Other Noncurrent Liabilities
Disaggregation of Revenue [Line Items]
Contract liabilities, noncurrent	44,359
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	516,368	445,135
Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	258,518	229,065
Utility Support Structures Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	252,698	222,948
Utility Support Structures Segment \| Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	6,294	8,924
Utility Support Structures Segment \| Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	246,404	214,024
Engineered Support Structures Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	222,156	227,366
Engineered Support Structures Segment \| Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	213,846	215,879
Engineered Support Structures Segment \| Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	8,310	11,487
Coatings Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	71,591	68,590
Coatings Segment \| Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	71,591	68,590
Coatings Segment \| Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Irrigation Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	228,441	155,296
Irrigation Segment \| Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	224,637	151,742
Irrigation Segment \| Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 3,804	$ 3,554