Quarterly report pursuant to Section 13 or 15(d)

Debt, Net - Fair Value of Debt (Details)

v3.20.2
Debt, Net - Fair Value of Debt (Details) - USD ($)
$ in Thousands
Sep. 30, 2020
Dec. 31, 2019
Carrying Amount    
Carrying amount and estimated fair value of debt    
Long-term debt $ 2,181,551 $ 1,831,139
Carrying Amount | Unsecured senior notes    
Carrying amount and estimated fair value of debt    
Long-term debt 1,465,805 1,192,910
Carrying Amount | Other fixed-rate debt    
Carrying amount and estimated fair value of debt    
Long-term debt 141,803 144,468
Carrying Amount | Variable-rate secured debt    
Carrying amount and estimated fair value of debt    
Long-term debt 573,943 493,761
Estimated Fair Value    
Carrying amount and estimated fair value of debt    
Long-term debt 2,217,245 1,873,310
Estimated Fair Value | Unsecured senior notes    
Carrying amount and estimated fair value of debt    
Long-term debt 1,505,414 1,227,441
Estimated Fair Value | Other fixed-rate debt    
Carrying amount and estimated fair value of debt    
Long-term debt 144,370 149,907
Estimated Fair Value | Variable-rate secured debt    
Carrying amount and estimated fair value of debt    
Long-term debt $ 567,461 $ 495,962