Business Segment Information - Net Operating Income (Loss) by Business Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income from Operations (loss) by business segment
Net operating income	$ 3,307	$ 4,285	$ 6,645	$ 8,032
Engineered Equipment Technology and Parts [Member]
Income from Operations (loss) by business segment
Net operating income	5,753	3,859	10,033	7,164
Contracting / Services [Member]
Income from Operations (loss) by business segment
Net operating income	346	563	919	1,684
Component Parts [Member]
Income from Operations (loss) by business segment
Net operating income	1,137	1,323	2,057	2,412
Corporate and other [Member]
Income from Operations (loss) by business segment
Net operating income	(3,686)	(1,517)	(6,151)	(3,212)
Inter-segment Elimination [Member]
Income from Operations (loss) by business segment
Net operating income	$ (243)	$ 57	$ (213)	$ (16)