BUSINESS SEGMENTS (Details) $ in Thousands	12 Months Ended
	Dec. 25, 2021 USD ($) segment	Dec. 26, 2020 USD ($)	Dec. 28, 2019 USD ($)
Business Segments
Number of reportable segments | segment	4
Net sales	$ 3,501,575	$ 2,895,355	$ 2,766,976
Operating Income (loss)	286,785	225,953	227,905
Interest expense, net	(41,420)	(38,701)	(36,211)
Other	14,718	5,516	8,164
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries	260,083	192,768	199,858
Total assets	3,447,249	2,953,160	2,807,216
Capital expenditures	107,790	106,700	97,425
Depreciation and amortization	92,577	82,892	82,264
Point in Time
Business Segments
Net sales	2,384,575	1,921,328	1,865,064
Engineered Support Structures
Business Segments
Net sales	1,064,440	983,523	1,002,076
Operating Income (loss)	115,417	65,342	65,627
Total assets	977,334	932,565	944,428
Capital expenditures	16,578	24,447	25,344
Depreciation and amortization	24,733	25,399	26,280
Engineered Support Structures | Point in Time
Business Segments
Net sales	1,026,312	940,513	952,056
Utility Support Structures
Business Segments
Net sales	1,121,004	1,002,138	885,608
Operating Income (loss)	67,624	100,855	87,788
Total assets	827,083	778,127	742,194
Capital expenditures	36,718	34,495	26,306
Depreciation and amortization	24,075	23,641	23,779
Utility Support Structures | Point in Time
Business Segments
Net sales	62,904	86,382	47,450
Coatings
Business Segments
Net sales		269,602	300,640
Operating Income (loss)	50,365	42,975	51,008
Total assets	366,026	360,594	363,070
Capital expenditures	19,178	22,132	23,610
Depreciation and amortization	16,928	15,793	15,907
Coatings | Point in Time
Business Segments
Net sales	299,081	269,602	300,640
Irrigation
Business Segments
Net sales	1,017,050	640,092	578,652
Operating Income (loss)	137,027	83,046	71,687
Total assets	1,027,272	465,322	347,887
Capital expenditures	17,509	16,740	15,644
Depreciation and amortization	17,813	12,098	10,943
Irrigation | Point in Time
Business Segments
Net sales	996,278	624,831	564,918
Corporate
Business Segments
Operating Income (loss)	(83,648)	(66,265)	(48,205)
Total assets	249,534	416,552	409,637
Capital expenditures	17,807	8,886	6,521
Depreciation and amortization	9,028	5,961	5,355
Operating segment
Business Segments
Sales	3,601,301	2,989,192	2,855,901
Operating segment | Engineered Support Structures
Business Segments
Sales	1,064,761	995,840	1,012,290
Operating segment | Engineered Support Structures | Lighting, Traffic, and Highway Safety Products
Business Segments
Sales	717,650	717,216	708,853
Operating segment | Engineered Support Structures | Communication Products
Business Segments
Sales	240,171	190,203	188,912
Operating segment | Engineered Support Structures | Access Systems
Business Segments
Sales	106,940	88,421	114,525
Operating segment | Utility Support Structures
Business Segments
Sales	1,121,510	1,002,209	890,580
Operating segment | Utility Support Structures | Steel
Business Segments
Sales	770,104	635,220	630,892
Operating segment | Utility Support Structures | Concrete
Business Segments
Sales	165,501	160,544	122,032
Operating segment | Utility Support Structures | Engineered Solar Tracker Solutions
Business Segments
Sales	62,904	86,382	47,450
Operating segment | Utility Support Structures | Offshore and Other Complex Steel Structures
Business Segments
Sales	123,001	120,063	90,206
Operating segment | Coatings
Business Segments
Sales	386,313	345,312	367,835
Operating segment | Irrigation
Business Segments
Sales	1,028,717	645,831	585,196
Operating segment | Irrigation | North America
Business Segments
Sales	545,574	378,424	378,613
Operating segment | Irrigation | International
Business Segments
Sales	483,143	267,407	206,583
Intersegment
Business Segments
Sales	99,726	93,837	88,925
Intersegment | Engineered Support Structures
Business Segments
Sales	321	12,317	10,214
Intersegment | Utility Support Structures
Business Segments
Sales	506	71	4,972
Intersegment | Coatings
Business Segments
Sales	87,232	75,710	67,195
Intersegment | Irrigation
Business Segments
Sales	$ 11,667	$ 5,739	$ 6,544