Business Segment Information - Schedule of Operating Segments Organized by Manufacturing Facilities and Include Three Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net sales:
Total net sales	$ 142,774	$ 153,293
Operating income (loss):
Pension credit	3,696	1,899
OPEB credit	1,674	1,577
Other	(1,327)	(1,948)
Total operating income	11,162	12,326
Non operating income (expense):
Interest expense	(345)	(360)
Other income (expense), net	75	(277)
Income before income taxes	10,892	11,689
KSW [Member]
Net sales:
Total net sales	140,620	152,991
Operating income (loss):
Total operating income	7,487	10,537
EWP [Member]
Net sales:
Total net sales	11,625	12,749
Operating income (loss):
Total operating income	408	446
Calumet [Member]
Net sales:
Total net sales	7,107	7,442
Operating income (loss):
Total operating income	(776)	(185)
Elimination of intersegment sales [Member]
Net sales:
Total net sales	$ (16,578)	$ (19,889)