Long-Term Debt - Outstanding Debt Maturities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Maturities of outstanding debt
2020	$ 89,356
2021	3,679
2022	4,297
2023	403,703
2024	903,379
Thereafter	1,360,058
Total debt	2,764,472	$ 2,401,393
Interest costs
Interest costs incurred	132,600	129,500	$ 136,100
Interest costs incurred capitalized	$ 5,500	$ 2,900	$ 1,700

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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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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