Annual report pursuant to Section 13 and 15(d)

Assets and Liabilities Measured at Fair Value (Details)

v3.8.0.1
Assets and Liabilities Measured at Fair Value (Details)
 1 Months Ended 12 Months Ended
Oct. 03, 2017
USD ($)
shares
Mar. 31, 2017
USD ($)
Aug. 31, 2017
USD ($)
Apr. 30, 2017
USD ($)
shares
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
shares
Jul. 31, 2015
USD ($)
Jun. 30, 2015
USD ($)
Apr. 30, 2015
USD ($)
Dec. 31, 2016
USD ($)
shares
Dec. 31, 2017
USD ($)
$ / item
Mar. 27, 2015
USD ($)
$ / item
shares
Feb. 28, 2015
$ / item
shares
Dec. 31, 2014
$ / item
shares
Revolving Credit Facility                            
Assets and Liabilities Measured at Fair Value                            
Maximum borrowing capacity                       $ 234,000,000    
Zero-strike call option                            
Assets and Liabilities Measured at Fair Value                            
Derivative underlying share amount | shares 527,156                          
Derivative premium paid $ 47,700,000         $ 47,900,000                
Derivative settlement proceeds   $ 50,000,000 $ 53,800,000   $ 50,000,000                  
Zero-strike call option | Call Option                            
Assets and Liabilities Measured at Fair Value                            
Derivative underlying share amount | shares 527,156     600,242   704,908       704,908        
Derivative premium paid $ 47,700,000     $ 50,000,000   $ 47,900,000                
Derivative, Price Risk Option Strike Price | $ / item                     90.54      
Cashless Collar | Time Warner Cable                            
Assets and Liabilities Measured at Fair Value                            
Derivative share amount hedged | shares                       1,700,000    
Payments from settlements of financial instruments             $ 67,100,000              
Cashless Collar | Put Option | Time Warner Cable                            
Assets and Liabilities Measured at Fair Value                            
Derivative, Price Risk Option Strike Price | $ / item                       136.80    
Cashless Collar | Call Option | Time Warner Cable                            
Assets and Liabilities Measured at Fair Value                            
Derivative, Price Risk Option Strike Price | $ / item                       161.62    
Total | Recurring                            
Assets and Liabilities Measured at Fair Value                            
Cash equivalents           198,011,000       $ 198,011,000 $ 76,304,000      
Derivative Asset           49,019,000       49,019,000        
Expiration Date February 2015 | Written call option | Time Warner Cable                            
Assets and Liabilities Measured at Fair Value                            
Derivative share amount hedged | shares                           625,000
Derivative, Price Risk Option Strike Price | $ / item                           92.02
Expiration Date February 2016 | Written call option | Time Warner Cable                            
Assets and Liabilities Measured at Fair Value                            
Derivative share amount hedged | shares                         625,000  
Derivative, Price Risk Option Strike Price | $ / item                         100.39  
Payments from settlements of financial instruments               $ 48,300,000            
Expiration Date May 2015 | Written call option | Time Warner Cable                            
Assets and Liabilities Measured at Fair Value                            
Derivative share amount hedged | shares                           625,000
Derivative, Price Risk Option Strike Price | $ / item                           90.84
Payments from settlements of financial instruments                 $ 36,700,000          
Quoted prices in active markets for identical assets (Level 1) | Recurring                            
Assets and Liabilities Measured at Fair Value                            
Cash equivalents                     $ 76,304,000      
Quoted prices in active markets for identical assets (Level 1) | Available for sale securities | Recurring                            
Assets and Liabilities Measured at Fair Value                            
Cash equivalents           198,011,000       198,011,000        
Significant other observable inputs (Level 2) | Available for sale securities | Recurring                            
Assets and Liabilities Measured at Fair Value                            
Derivative Asset           $ 49,019,000       $ 49,019,000        
Minimum                            
Level 2 input                            
Volatility                   21.10%        
Interest rate                   1.00%        
Dividend yield                   0.00%        
Maximum                            
Level 2 input                            
Volatility                   21.50%        
Interest rate                   1.00%        
Dividend yield                   0.00%