Legal Contingencies - Additional Information (Detail) (USD $)		1 Months Ended				6 Months Ended		1 Months Ended				6 Months Ended
	Aug. 31, 2012 Payment Received from the Parent Company of Delta-T [Member]	Aug. 31, 2012 Amount of Claim of Indebt [Member]	Dec. 31, 2011 GPS [Member]	Apr. 30, 2009 GPS [Member]	Jan. 31, 2009 GPS [Member]	Jul. 31, 2014 GPS [Member]	Aug. 31, 2012 GPS [Member]	Jan. 31, 2009 GPS [Member] Procurement and Construction Services Related to Nebraska Project [Member]	Mar. 31, 2008 GPS [Member] Procurement and Construction Services Related to Nebraska Project [Member]	Apr. 30, 2009 Delta-T Corporation [Member]	Jan. 31, 2009 Delta-T Corporation [Member]	Jul. 31, 2014 Delta-T Corporation [Member]
Loss Contingencies [Line Items]
GPS mechanics lien against Nebraska project		$ 1,800,000							$ 23,800,000
Net processed held by the bankruptcy court						5,500,000
Settlement payment made by GPS to Delta-T under the project Close-Out Agreement					3,500,000
Assignment to GPS of first receipts of Delta-T											3,500,000
Amount of lien rights assigned by Delta-T to GPS								21,200,000
Arbitration award in favor of DCR against Delta-T										6,800,000
Lawsuit filing dates						December, 2011						April, 2009
Amended amount of complaint filed against surety bonding company by DCR				6,800,000
Damages sought by DCR from GPS						$6.1 million plus interest, costs and attorney fees
Claims sought			6,100,000
Total payment made	275,000						1,875,000
Provision for loss						$ 0