Costs, Estimated Earnings and Billings on Uncompleted Contracts (Details) (USD $)	Jan. 31, 2013	Jan. 31, 2012
Aggregate amounts of costs incurred and earnings accrued on uncompleted contracts compared with billings for contracts
Costs incurred on uncompleted contracts	$ 259,390,000	$ 106,379,000
Estimated accrued earnings	48,724,000	12,121,000
Contracts Receivables, Gross	308,114,000	118,500,000
Less - Billings to date	380,295,000	183,723,000
Billings in excess of costs and estimated earnings on uncompleted contracts, net	72,181,000	65,223,000
Costs and estimated earnings in excess of billings	1,178,000	2,781,000
Billings in excess of costs and estimated earnings	73,359,000	68,004,000
Billings in excess of costs and estimated earnings on uncompleted contracts, net	$ 72,181,000	$ 65,223,000