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Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (USD $)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Property, Plant and Equipment [Line Items]      
In-process revenue contracts reclassified from intangible assets   $ 6,500,000  
Depreciation of vessels and equipment 76,400,000 73,200,000 72,800,000
Interest costs capitalized to vessels and equipment $ 24,000 $ 3,100,000 $ 4,200,000
Tax rate in Spain 30.00%    
Effective income tax rate on revenue by Spanish vessels tax credit 90.00%    
Effective tax rate on revenues by Spanish vessels 3.00%    
Conventional Tankers [Member]
      
Property, Plant and Equipment [Line Items]      
Estimated useful life in years 25 years    
LPG carriers [Member]
      
Property, Plant and Equipment [Line Items]      
Estimated useful life in years 30 years    
LNG carriers [Member]
      
Property, Plant and Equipment [Line Items]      
Estimated useful life in years 35 years