Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v3.5.0.2
Debt (Details)
1 Months Ended 4 Months Ended 9 Months Ended
Mar. 21, 2016
USD ($)
item
Apr. 07, 2015
USD ($)
Oct. 31, 2014
USD ($)
Oct. 30, 2014
USD ($)
item
Jul. 31, 2015
USD ($)
Nov. 30, 2014
USD ($)
Jul. 31, 2015
Sep. 30, 2016
USD ($)
shares
Sep. 30, 2015
USD ($)
Dec. 31, 2015
USD ($)
Mar. 27, 2015
USD ($)
Debt disclosures                      
Debt outstanding               $ 598,178,000   $ 399,703,000  
Distribution to parent     $ 300,000,000                
Repayments of debt                 $ 40,000,000    
Margin Loan Agreements | Charter                      
Debt disclosures                      
Number of common shares pledged as collateral | shares               9,500,000      
Value of pledged collateral               $ 2,600,000,000      
Revolving Credit Facility                      
Debt disclosures                      
Maximum borrowing capacity                     $ 234,000,000
Interest rate basis             three-month LIBOR        
Proceeds from Issuance of Debt   $ 40,000,000                  
Debt Instrument, Unused Borrowing Capacity Fee, Percent         0.12%   0.12%        
Repayments of debt         $ 40,000,000            
Revolving Credit Facility | Three-month LIBOR                      
Debt disclosures                      
Basis spread on variable rate             0.64%        
BroadbandSPV | Margin Loan Agreements                      
Debt disclosures                      
Long-term Debt, Gross               400,000,000      
Remaining borrowing capacity               $ 0      
Interest rate basis               three-month LIBOR      
Debt Instrument, Interest Rate, Effective Percentage               2.18%      
BroadbandSPV | Margin Loan Agreements | Three-month LIBOR                      
Debt disclosures                      
Basis spread on variable rate               1.55%      
BroadbandSPV | Margin Loan Agreements | Term loan                      
Debt disclosures                      
Unused commitment fee percentage               0.25%      
BroadbandSPV | Margin Loan Agreements | Draw loan                      
Debt disclosures                      
Unused commitment fee percentage               0.50%      
BroadbandSPV | Margin Loan Agreements                      
Debt disclosures                      
Number of debt agreements | item       2              
Maximum borrowing capacity       $ 400,000,000              
Proceeds From Issuance Of Secured Debt     $ 320,000,000     $ 52,000,000          
Cheetah 5 | Margin Loan Agreements                      
Debt disclosures                      
Number of debt agreements | item 2                    
Maximum borrowing capacity $ 300,000,000                    
Long-term Debt, Gross               $ 200,000,000      
Interest rate basis               LIBOR      
Debt Instrument, Interest Rate, Effective Percentage               2.73%      
Cheetah 5 | Margin Loan Agreements | LIBOR                      
Debt disclosures                      
Basis spread on variable rate               2.10%      
Cheetah 5 | Margin Loan Agreements | Term loan                      
Debt disclosures                      
Maximum borrowing capacity $ 200,000,000                    
Cheetah 5 | Margin Loan Agreements | Draw loan                      
Debt disclosures                      
Maximum borrowing capacity               $ 100,000,000      
Remaining borrowing capacity               $ 100,000,000