Accounts Receivable - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended			12 Months Ended
	Jan. 31, 2010	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014 Minimum [Member]	Jan. 31, 2014 Maximum [Member]	Jan. 31, 2014 Construction Contracts Retainage [Member]	Jan. 31, 2013 Construction Contracts Retainage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract payment amounts retained by project owners						$ 22.7	$ 20.2
Length of retention period of amount given to project owners				10 months	29 months
Allowance for doubtful accounts		5.5	5.5
The amount of the net proceeds remaining from public auction of the partially completed project	$ 5.5