Costs Estimated Earnings and Billings on Uncompleted Contracts (Details) (USD $)	Jul. 31, 2013	Jan. 31, 2013
Aggregate amounts of costs incurred and earnings accrued on uncompleted contracts compared with billings for contracts
Costs incurred on uncompleted contracts	$ 321,895,000	$ 259,390,000
Estimated accrued earnings	78,940,000	48,724,000
Contracts Receivables, Gross	400,835,000	308,114,000
Less-Billings to date	440,401,000	380,295,000
Billings in excess of costs and estimated earnings on uncompleted contracts, net	39,566,000	72,181,000
Costs and estimated earnings in excess of billings	509,000	1,178,000
Billings in excess of costs and estimated earnings	$ 40,075,000	$ 73,359,000