Legal Contingencies - Additional Information (Detail) (USD $)	1 Months Ended				9 Months Ended		1 Months Ended			9 Months Ended
	Aug. 31, 2012 Amount of Claim of Indebt [Member]	Dec. 31, 2011 GPS [Member]	Apr. 30, 2009 GPS [Member]	Jan. 31, 2009 GPS [Member]	Oct. 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]	Oct. 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
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						$ 1,875,000