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								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net sales:
Total net sales	$ 108,545	$ 133,072	$ 152,747	$ 153,293	$ 132,894	$ 140,973	$ 155,955	$ 134,163	$ 547,657	$ 563,985	$ 450,745
Operating income (loss):
Defined benefit pension credit									6,858	24,388	4,654
Other post retirement benefit credit									6,075	5,799	5,258
Other									(1,884)	(2,910)	(2,873)
Total operating income									33,898	51,568	21,885
Nonoperating income (expense):
Interest expense									(1,213)	(1,218)	(1,863)
Other, net									(518)	699	637
Income before income taxes									32,167	51,049	20,659
KSW [Member]
Net sales:
Total net sales									520,207	544,011	433,729
Operating income (loss):
Total operating income									23,037	22,302	15,111
EWP [Member]
Net sales:
Total net sales									59,468	55,928	41,310
Operating income (loss):
Total operating income									3,004	1,840	(362)
Calumet [Member]
Net sales:
Total net sales									28,543	30,905	22,987
Operating income (loss):
Total operating income									(3,192)	149	97
Elimination of intersegment sales [Member]
Net sales:
Total net sales									$ (60,561)	$ (66,859)	$ (47,281)