Long-Term Debt - WCS - Additional Information (Detail) (WCS, USD $)	12 Months Ended				3 Months Ended			12 Months Ended
	Dec. 31, 2012 Vendor construction retainage promissory note	Dec. 31, 2011 Vendor construction retainage promissory note	Dec. 31, 2010 Vendor construction retainage promissory note	Dec. 31, 2013 Final Payment Vendor construction retainage promissory note	Mar. 31, 2010 Former customer promissory note	Dec. 31, 2013 Former customer promissory note	Apr. 30, 2010 Former customer promissory note	Dec. 31, 2013 Financing capital lease Andrews County capital lease
Debt Instrument [Line Items]
Gross proceeds sale of property and equipment								$ 75,000,000
Lease Agreement period								25 years
Lease agreement cost								2,600,000
Capital lease agreement interest rate								7.00%
Aggregate rental due								6,200,000
Principal amount of promissory note			6,600,000				12,000,000
Long-term promissory note fixed interest rate							6.00%
Contract termination expense					1,100,000
Carrying amount of debt			5,820,000			2,400,000
Promissory note due date			Dec. 31, 2013
Note calls for payments	2,400,000	1,700,000		2,500,000
Percentage of discount on promissory note			6.00%
Accrued construction retainage payable			$ 1,400,000