Quarterly report pursuant to Section 13 or 15(d)

Debt, Net - Fair Value of Debt (Details)

v3.21.1
Debt, Net - Fair Value of Debt (Details) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Carrying Amount    
Carrying amount and estimated fair value of debt    
Long-term debt $ 2,207,903 $ 2,086,918
Carrying Amount | Unsecured senior notes    
Carrying amount and estimated fair value of debt    
Long-term debt 1,549,801 1,289,461
Carrying Amount | Other fixed-rate debt    
Carrying amount and estimated fair value of debt    
Long-term debt 139,963 140,891
Carrying Amount | Variable-rate secured debt    
Carrying amount and estimated fair value of debt    
Long-term debt 518,139 656,566
Estimated Fair Value    
Carrying amount and estimated fair value of debt    
Long-term debt 2,242,280 2,131,282
Estimated Fair Value | Unsecured senior notes    
Carrying amount and estimated fair value of debt    
Long-term debt 1,583,253 1,334,342
Estimated Fair Value | Other fixed-rate debt    
Carrying amount and estimated fair value of debt    
Long-term debt 141,465 142,838
Estimated Fair Value | Variable-rate secured debt    
Carrying amount and estimated fair value of debt    
Long-term debt $ 517,562 $ 654,102