Costs, Estimated Earnings and Billings on Uncompleted Contracts - Aggregate Amounts of Costs Incurred and Earnings Accrued on Uncompleted Contracts Compared with Billings for Contracts (Detail) (USD $)	Jan. 31, 2014	Jan. 31, 2013
Contractors [Abstract]
Costs incurred on uncompleted contracts	$ 162,137,000	$ 259,390,000
Estimated accrued earnings	21,961,000	48,724,000
Contracts Receivables, Gross	184,098,000	308,114,000
Less-Billings to date	318,307,000	380,295,000
Billings in excess of costs and estimated earnings on uncompleted contracts, net	134,209,000	72,181,000
Costs and estimated earnings in excess of billings	527,000	1,178,000
Billings in excess of costs and estimated earnings	$ 134,736,000	$ 73,359,000