BUSINESS SEGMENTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 25, 2011	Jun. 30, 2012 item	Jun. 25, 2011
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%
Sales	$ 804,546	$ 694,960	$ 1,558,853	$ 1,288,021
Intersegment Sales	37,231	26,351	74,188	51,463
Net sales	767,315	668,609	1,484,665	1,236,558
Operating Income (Loss)	97,352	68,619	180,170	113,920
Engineered Infrastructure Products segment:
Business Segments
Sales	225,782	206,417	423,681	375,347
Intersegment Sales	14,692	5,480	27,084	11,424
Net sales	211,090	200,937	396,597	363,923
Operating Income (Loss)	14,168	11,515	22,192	13,718
Engineered Infrastructure Products segment: | Lighting, Traffic, and Roadway Products
Business Segments
Sales	148,541	145,538	281,838	262,849
Engineered Infrastructure Products segment: | Communication Products
Business Segments
Sales	36,488	28,297	63,183	48,720
Engineered Infrastructure Products segment: | Access Systems
Business Segments
Sales	40,753	32,582	78,660	63,778
Utility Support Structures segment
Business Segments
Sales	212,237	136,560	403,469	262,207
Intersegment Sales	467	1,951	2,447	2,259
Net sales	211,770	134,609	401,022	259,948
Operating Income (Loss)	26,574	12,984	51,678	26,483
Utility Support Structures segment | Steel
Business Segments
Sales	185,079	123,221	352,043	233,119
Utility Support Structures segment | Concrete
Business Segments
Sales	27,158	13,339	51,426	29,088
Coatings segment
Business Segments
Sales	84,837	84,161	167,684	157,611
Intersegment Sales	13,252	10,926	25,949	22,431
Net sales	71,585	73,235	141,735	135,180
Operating Income (Loss)	19,517	15,070	36,029	25,362
Irrigation segment
Business Segments
Sales	194,496	183,701	390,762	334,749
Intersegment Sales	6	5	431	8
Net sales	194,490	183,696	390,331	334,741
Operating Income (Loss)	37,607	32,964	76,015	56,858
Other
Business Segments
Sales	87,194	84,121	173,257	158,107
Intersegment Sales	8,814	7,989	18,277	15,341
Net sales	78,380	76,132	154,980	142,766
Operating Income (Loss)	12,259	11,380	23,670	20,294
Net corporate expense
Business Segments
Operating Income (Loss)	$ (12,773)	$ (15,294)	$ (29,414)	$ (28,795)