SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020	Dec. 26, 2020
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 868,782	$ 733,970	$ 2,538,297	$ 2,096,978
Contract assets	155,417		155,417		$ 123,495
Contract liabilities	203,198		203,198		170,919
Contract liabilities, current	138,286		138,286		$ 130,018
Revenue recognized from contract liability	18,981	16,333	88,350	55,610
Remaining performance obligations	$ 124,767		$ 124,767
Minimum
Disaggregation of Revenue [Line Items]
Remaining performance obligations, expected timing of satisfaction period	12 months		12 months
Maximum
Disaggregation of Revenue [Line Items]
Remaining performance obligations, expected timing of satisfaction period	24 months		24 months
Contract Liabilities
Disaggregation of Revenue [Line Items]
Contract liabilities, current	$ 138,286		$ 138,286
Other Noncurrent Liabilities
Disaggregation of Revenue [Line Items]
Contract liabilities, noncurrent	64,912		64,912
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	589,290	490,769	1,727,295	1,385,005
Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	279,492	243,201	811,002	711,973
Utility Support Structures Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	276,502	272,479	797,063	723,900
Utility Support Structures Segment | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	12,834	43,287	28,255	56,830
Utility Support Structures Segment | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	263,668	229,192	768,808	667,070
Engineered Support Structures Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	281,049	254,945	772,545	731,184
Engineered Support Structures Segment | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	271,277	244,785	745,125	697,491
Engineered Support Structures Segment | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	9,772	10,160	27,420	33,693
Coatings Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	74,906	68,698	224,102	199,955
Coatings Segment | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	74,906	68,698	224,102	199,955
Coatings Segment | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0	0	0
Irrigation Segment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	236,325	137,848	744,587	441,939
Irrigation Segment | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	230,273	133,999	729,813	430,729
Irrigation Segment | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 6,052	$ 3,849	$ 14,774	$ 11,210