Long-Term Debt - Outstanding Debt Maturities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Maturities of outstanding debt
2021	$ 86,894
2022	4,355
2023	3,799
2024	403,438
2025	403,488
Thereafter	2,256,684
Total debt	3,158,658	$ 2,764,472
Interest costs
Interest costs incurred	118,800	132,600	$ 129,500
Interest costs incurred capitalized	$ 23,900	$ 5,500	$ 2,900

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Total interest costs incurred during the period and either capitalized or charged against earnings.

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