Special Purpose Entities - Additional Information (Detail) (USD $)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Variable Interest Entity [Line Items]
Number of natural gas-fired power plant projects under development	2
Gains on the deconsolidation of variable interest entities	$ 2,444,000
Number of joint ventures	2
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Prospective amount of loan to Moxie Projects, maximum	10,000,000
Income attributable to the noncontrolling interest	77,000	1,448,000	302,000
Gains on the deconsolidation of variable interest entities	2,444,000
Gemma Power Inc [Member] | Panda Liberty LLC [Member]
Variable Interest Entity [Line Items]
Cash received from Moxie Project Entities in respect of sale of membership interest to third party investor	37,863,000
Cash received from Moxie Project Entities in respect of development success fees	27,052,000
Cash received from Moxie Project Entities for repayment of notes receivable and accrued interest	10,811,000
Aggregate interest income	$ 952,000