v2.4.0.8
Related Party Transactions - Additional Information (Detail) (USD $)
Share data in Millions, unless otherwise specified
1 Months Ended 1 Months Ended
Jun. 30, 2013
Dec. 31, 2012
Jun. 30, 2012
Class A [Member]
Jun. 30, 2013
Pool Managers [Member]
Dec. 31, 2012
Pool Managers [Member]
Jun. 30, 2012
Dropdown Predecessor [Member]
Jun. 26, 2012
Dropdown Predecessor [Member]
Vessel
Jun. 15, 2012
Dropdown Predecessor [Member]
Vessel
Jun. 30, 2012
Conventional oil tankers [Member]
Tanker
Jun. 30, 2012
Product tankers [Member]
Tanker
Jun. 30, 2013
Asset Management [Member]
Dec. 31, 2012
Asset Management [Member]
Related Party Transaction [Line Items]                        
Reimbursement of Manager's crewing and manning costs                     $ 4,100,000 $ 4,900,000
Working capital advanced to Pool Managers 20,981,000 24,787,000   19,700,000 16,600,000              
Number of Tankers             3 10 7 6    
Aggregate purchase price           454,200,000            
Business acquisition outstanding debt           428,100,000            
Business acquisition, number of shares issued     4.5                  
Business acquisition, cash paid           $ 1,100,000