Goodwill and Other Intangible Assets - Goodwill by Operating Segment (Detail) (USD $)	12 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended			12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2012 Energy [Member]	Jan. 31, 2013 Energy [Member]	Jan. 31, 2012 Water Resources [Member]	Jan. 31, 2013 Water Resources [Member]	Jan. 31, 2012 Inliner [Member]	Jan. 31, 2013 Inliner [Member]	Jan. 31, 2012 Heavy Civil [Member]	Jan. 31, 2013 Heavy Civil [Member]	Jan. 31, 2013 Geoconstruction [Member]	Jan. 31, 2011 Geoconstruction [Member]	Jan. 31, 2013 Mineral Exploration [Member]	Jan. 31, 2012 Other [Member]	Jan. 31, 2013 Other [Member]
Goodwill [Line Items]
Beginning Balance	$ 19,536,000	$ 103,378,000	$ 950,000		$ 17,084,000		$ 29,727,000	$ 8,915,000	$ 44,551,000		$ 10,621,000	$ 10,621,000		$ 445,000
Additions	4,025,000	2,318,000					2,318,000				4,025,000
Impairment of goodwill		(86,160,000)	(950,000)		(17,084,000)		(23,130,000)		(44,551,000)					(445,000)
Ending Balance	23,561,000	19,536,000					8,915,000	8,915,000			14,646,000	10,621,000
Accumulated goodwill impairment losses	$ (106,385,000)			$ (950,000)		$ (17,084,000)		$ (23,130,000)		$ (44,551,000)			$ (20,225,000)		$ (445,000)