Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt (Summary of Debt) (Details)

v3.10.0.1
Long-Term Debt (Summary of Debt) (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Debt Instrument [Line Items]    
Outstanding Principal $ 2,926,398  
Deferred financing costs (3,262) $ 0
Total debt 2,968,469 0
Debt classified as current (included in other current liabilities) (2,965) 0
Total long-term debt 2,965,504 0
Margin Loan    
Debt Instrument [Line Items]    
Outstanding Principal 1,000,000  
Carrying Value 1,000,000 $ 0
Exchangeable senior debentures    
Debt Instrument [Line Items]    
Outstanding Principal 477,250  
Carrying Value 491,987  
Senior notes    
Debt Instrument [Line Items]    
Outstanding Principal 775,000  
Carrying Value 805,596  
Senior credit facility    
Debt Instrument [Line Items]    
Outstanding Principal 666,354  
Carrying Value 666,354  
Wells Fargo note payable    
Debt Instrument [Line Items]    
Outstanding Principal 7,794  
Carrying Value $ 7,794