BUSINESS SEGMENTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014 item	Jun. 29, 2013
Business Segments
Number of reportable segments			4
Maximum percentage of sales of other businesses and activities to consolidated sales as basis for aggregation			10.00%
Net sales	$ 842,599	$ 878,659	$ 1,594,339	$ 1,698,289
Operating Income	104,776	144,265	203,624	262,455
Engineered Infrastructure Products segment:
Business Segments
Net sales	286,186	228,467	495,083	422,685
Operating Income	28,625	22,603	42,334	35,337
Utility Support Structures segment
Business Segments
Net sales	212,005	227,944	426,237	467,171
Operating Income	26,375	42,121	59,132	88,276
Coatings segment
Business Segments
Net sales	70,387	79,350	137,605	154,265
Operating Income	15,820	23,552	29,706	36,972
Irrigation segment
Business Segments
Net sales	219,913	270,174	432,637	514,881
Operating Income	41,473	64,174	84,619	118,733
Other
Business Segments
Net sales	54,108	72,724	102,777	139,287
Operating Income	8,343	13,025	16,893	23,812
Corporate
Business Segments
Operating Income	(15,860)	(21,210)	(29,060)	(40,675)
Operating segment
Business Segments
Sales	884,242	926,531	1,680,937	1,801,660
Operating segment | Engineered Infrastructure Products segment:
Business Segments
Sales	304,352	250,636	532,814	474,306
Operating segment | Engineered Infrastructure Products segment: | Lighting, Traffic, and Roadway Products
Business Segments
Sales	164,753	161,487	303,730	308,657
Operating segment | Engineered Infrastructure Products segment: | Communication Products
Business Segments
Sales	43,618	34,771	73,504	63,393
Operating segment | Engineered Infrastructure Products segment: | Offshore Structures
Business Segments
Sales	47,217		64,521
Operating segment | Engineered Infrastructure Products segment: | Access Systems
Business Segments
Sales	48,764	54,378	91,059	102,256
Operating segment | Utility Support Structures segment
Business Segments
Sales	213,030	228,243	427,757	467,881
Operating segment | Utility Support Structures segment | Steel
Business Segments
Sales	179,574	200,650	371,011	411,661
Operating segment | Utility Support Structures segment | Concrete
Business Segments
Sales	33,456	27,593	56,746	56,220
Operating segment | Coatings segment
Business Segments
Sales	85,157	93,798	167,328	183,043
Operating segment | Irrigation segment
Business Segments
Sales	219,917	270,175	432,650	514,882
Operating segment | Other
Business Segments
Sales	61,786	83,679	120,388	161,548
Intersegment
Business Segments
Sales	41,643	47,872	86,598	103,371
Intersegment | Engineered Infrastructure Products segment:
Business Segments
Sales	18,166	22,169	37,731	51,621
Intersegment | Utility Support Structures segment
Business Segments
Sales	1,025	299	1,520	710
Intersegment | Coatings segment
Business Segments
Sales	14,770	14,448	29,723	28,778
Intersegment | Irrigation segment
Business Segments
Sales	4	1	13	1
Intersegment | Other
Business Segments
Sales	$ 7,678	$ 10,955	$ 17,611	$ 22,261