Stockholders' Equity (Details) (USD $)
12 Months Ended
Dec. 31, 2014
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Dec. 31, 2013
Dec. 31, 2011
Sep. 18, 2009
Stockholders' Equity        
Shares issued 109,669,429 109,653,363    
Shares outstanding 109,669,429 109,653,363    
Authorized capital stock, common stock (in shares) 750,000,000 750,000,000   750,000,000
Authorized capital stock, par value of common stock (in dollars per share) $ 0.01 0.01   $ 0.01
Authorized capital stock, preferred stock (in shares) 100,000,000 100,000,000   100,000,000
Authorized capital stock, par value of preferred stock (in dollars per share) $ 0.01 0.01   $ 0.01
Stockholders' equity        
Maximum consolidated net leverage ratio set as condition for payment of cash dividends and repurchase of shares 6      
Number of consecutive quarters considered for calculation of consolidated net leverage ratio 4      
Ratio of aggregate market value of vessels to outstanding indebtedness (as a percent) 125.00%      
Number of consecutive quarters considered for calculation of ratio of aggregate market value of vessels to outstanding indebtedness 4      
Number of warrants issued to lenders     15,000,000  
Exercise price of warrant (in dollars per share)     7.00  
Manager's employees, directors and employees of the Company        
Stockholders' equity        
Newly issued shares 16,066 49,323