BUSINESS SEGMENTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 segment	Mar. 26, 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	$ 754,307	$ 593,061
Intersegment Sales	36,957	25,112
Net sales	717,350	567,949
Operating Income (Loss)	82,818	45,301
Engineered Infrastructure Products segment:
Business Segments
Sales	197,899	168,930
Intersegment Sales	12,392	5,944
Net sales	185,507	162,986
Operating Income (Loss)	8,024	2,203
Engineered Infrastructure Products segment: | Lighting, Traffic, and Roadway Products
Business Segments
Sales	133,297	117,311
Engineered Infrastructure Products segment: | Communication Products
Business Segments
Sales	26,695	20,423
Engineered Infrastructure Products segment: | Access Systems
Business Segments
Sales	37,907	31,196
Utility Support Structures segment
Business Segments
Sales	191,232	125,647
Intersegment Sales	1,980	308
Net sales	189,252	125,339
Operating Income (Loss)	25,104	13,499
Utility Support Structures segment | Steel
Business Segments
Sales	166,964	109,898
Utility Support Structures segment | Concrete
Business Segments
Sales	24,268	15,749
Coatings segment
Business Segments
Sales	82,847	73,450
Intersegment Sales	12,697	11,505
Net sales	70,150	61,945
Operating Income (Loss)	16,512	10,292
Irrigation segment
Business Segments
Sales	196,266	151,048
Intersegment Sales	425	3
Net sales	195,841	151,045
Operating Income (Loss)	38,408	23,894
Other
Business Segments
Sales	86,063	73,986
Intersegment Sales	9,463	7,352
Net sales	76,600	66,634
Operating Income (Loss)	11,411	8,914
Net corporate expense
Business Segments
Operating Income (Loss)	$ (16,641)	$ (13,501)