BUSINESS SEGMENTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 segment	Dec. 25, 2010 segment	Dec. 26, 2009
Business Segments
Number of reportable segments	4	4
Maximum percentage of sales of other businesses and activities to consolidated sales as basis for aggregation	10.00%	10.00%
Sales	$ 2,767,778	$ 2,032,428	$ 1,843,950
Intersegment Sales	106,298	56,923	57,349
Net sales	2,661,480	1,975,505	1,786,601
Operating Income (Loss)	263,310	178,413	237,994
Interest expense, net	(26,910)	(26,107)	(14,250)
Other	(2,643)	676	2,340
Earnings before income taxes and equity in earnings of nonconsolidated subsidiaries	233,757	152,982	226,084
Total assets	2,306,076	2,090,743	1,302,139
CAPITAL EXPENDITURES:	83,069	36,092	44,129
Depreciation and amortization	74,560	59,663	44,748
Utility Support Structures segment
Business Segments
Sales	624,870	474,920	700,548
Intersegment Sales	4,105	2,219	2,331
Net sales	620,765	472,701	698,217
Operating Income (Loss)	70,643	51,741	164,834
Total assets	432,657	360,256	311,862
CAPITAL EXPENDITURES:	31,501	5,228	13,899
Depreciation and amortization	12,548	11,320	10,287
Utility Support Structures segment | Steel
Business Segments
Sales	546,926	407,703	578,740
Utility Support Structures segment | Concrete
Business Segments
Sales	77,944	67,217	121,808
Irrigation segment
Business Segments
Sales	666,007	443,371	362,187
Intersegment Sales	111	12	16
Net sales	665,897	443,359	362,171
Operating Income (Loss)	107,759	61,973	35,086
Total assets	267,615	209,850	183,243
CAPITAL EXPENDITURES:	8,766	4,248	10,189
Depreciation and amortization	6,006	4,823	4,298
Engineered Infrastructure Products segment:
Business Segments
Sales	817,593	677,314	597,046
Intersegment Sales	24,996	8,044	14,744
Net sales	792,596	669,270	582,302
Operating Income (Loss)	40,753	52,151	45,143
Total assets	750,992	762,600	514,564
CAPITAL EXPENDITURES:	13,328	17,050	12,735
Depreciation and amortization	30,637	25,281	21,203
Engineered Infrastructure Products segment: | Lighting, Traffic, and Roadway Products
Business Segments
Sales	573,121	490,359	455,583
Engineered Infrastructure Products segment: | Communication Products
Business Segments
Sales	109,131	105,852	141,463
Engineered Infrastructure Products segment: | Access Systems
Business Segments
Sales	135,341	81,103
Coatings segment
Business Segments
Sales	327,322	238,273	115,530
Intersegment Sales	46,534	29,906	24,954
Net sales	280,788	208,367	90,576
Operating Income (Loss)	58,656	42,602	24,669
Total assets	283,588	325,675	98,861
CAPITAL EXPENDITURES:	22,881	5,570	1,493
Depreciation and amortization	12,175	8,376	4,074
Other
Business Segments
Sales	331,986	198,550	68,639
Intersegment Sales	30,552	16,742	15,304
Net sales	301,434	181,808	53,335
Operating Income (Loss)	45,670	28,499	12,971
Total assets	203,185	222,984	27,860
CAPITAL EXPENDITURES:	4,501	1,582	583
Depreciation and amortization	8,539	6,260	1,826
Net corporate expense
Business Segments
Operating Income (Loss)	(60,171)	(58,553)	(44,709)
Total assets	368,039	209,378	165,749
CAPITAL EXPENDITURES:	2,092	2,414	5,230
Depreciation and amortization	$ 4,655	$ 3,603	$ 3,059