Quarterly report pursuant to Section 13 or 15(d)

Equity Investments (Investments Accounted For By The Equity Method) (Details)

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Equity Investments (Investments Accounted For By The Equity Method) (Details) (USD $)
Mar. 31, 2012
Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]    
Equity investments $ 163,174,000 $ 86,824,000
Tatex Thailand II, LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments 829,000 1,030,000
Tatex Thailand III, LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments 8,731,000 8,282,000
Grizzly Oil Sands ULC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments 136,732,000 69,008,000
Bison Drilling And Field Services LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments 6,361,000 6,366,000
Muskie Holdings LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments 2,441,000 2,138,000
Timber Wolf Terminals LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments 1,000,000  
Windsor Midstream LLC [Member]
    
Schedule of Equity Method Investments [Line Items]    
Equity investments $ 7,080,000