Quarterly report pursuant to Section 13 or 15(d)

Debt - Summary of Debt (Details)

v3.21.1
Debt - Summary of Debt (Details) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Debt Instrument [Line Items]    
Outstanding principal $ 4,543,809  
Deferred financing costs (1,714) $ (2,017)
Total 4,586,597 4,816,233
Debt classified as current (29,425) (31,026)
Total long-term debt 4,557,172 4,785,207
2.75% Exchangeable Senior Debentures due 2050    
Debt Instrument [Line Items]    
Outstanding principal 575,000  
Carrying value $ 588,064 $ 608,804
Interest rate (as a percent) 2.75% 2.75%
1.25% Exchangeable Senior Debentures due 2050    
Debt Instrument [Line Items]    
Outstanding principal $ 825,000  
Carrying value $ 811,536 $ 836,971
Interest rate (as a percent) 1.25% 1.25%
1.75% Exchangeable Senior Debentures due 2046    
Debt Instrument [Line Items]    
Outstanding principal $ 14,536  
Carrying value $ 24,741 $ 26,350
Interest rate (as a percent) 1.75% 1.75%
Senior notes    
Debt Instrument [Line Items]    
Outstanding principal $ 600,000  
Carrying value 634,697 $ 635,683
Senior Credit Facility    
Debt Instrument [Line Items]    
Outstanding principal 523,000  
Carrying value 523,000 704,000
Wells Fargo note payable    
Debt Instrument [Line Items]    
Outstanding principal 6,273  
Carrying value 6,273 6,442
SPV | Margin Loan Facility    
Debt Instrument [Line Items]    
Outstanding principal 2,000,000  
Carrying value $ 2,000,000 $ 2,000,000