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Commitments and Contingencies (Details) - USD ($)
Jun. 30, 2016
Dec. 31, 2015
Insurance Claims [Member]    
Commitments and Contingencies (Textual) [Abstract]    
Liability and cargo insurance coverage for claims $ 500,000  
Cargo Claims [Member]    
Commitments and Contingencies (Textual) [Abstract]    
Liability and cargo insurance coverage for claims 100,000  
Uninsured Risk [Member]    
Commitments and Contingencies (Textual) [Abstract]    
Reserves for estimated uninsured losses $ 6,400,000 $ 7,200,000