ACCOUNTS RECEIVABLE - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	May. 31, 2015	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2015	Jul. 31, 2014	Jan. 31, 2015	Jan. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract payment amounts retained by project owners		$ 32,200,000		$ 32,200,000		$ 26,100,000
Allowance for doubtful accounts						$ 5,500,000
Cash received	$ 1,600,000
Provision for accounts receivable loss		$ 0	$ 0	$ 0	$ 0
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Length of retention period of amount given to project owners				9 months
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Length of retention period of amount given to project owners				12 months
Altra Nebraska, LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable from the owner of a partially completed construction project							$ 5,500,000