Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Goodwill and Other Intangible Assets - Goodwill by Operating Segment (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Jul. 31, 2013	Oct. 31, 2013
Goodwill [Line Items]
Beginning Balance		$ 23,561
Additions
Impairment of goodwill	(14,600)	(14,646)
Ending Balance		8,915
Water Resources [Member]
Goodwill [Line Items]
Additions
Inliner [Member]
Goodwill [Line Items]
Beginning Balance		8,915
Additions
Ending Balance		8,915
Heavy Civil [Member]
Goodwill [Line Items]
Additions
Geoconstruction [Member]
Goodwill [Line Items]
Beginning Balance		14,646
Additions
Impairment of goodwill		(14,646)
Mineral Services [Member]
Goodwill [Line Items]
Additions
Energy Services [Member]
Goodwill [Line Items]
Additions
Other [Member]
Goodwill [Line Items]
Additions