Debt (Summary of Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt issued	$ 2,593,209
Deferred financing costs	(7,197)	$ (8,491)
Total debt	2,605,420	2,607,379
Debt classified as current	(3,125)	(3,008)
Long-term debt	2,602,295	2,604,371
Margin Loan Facility
Debt Instrument [Line Items]
Debt issued	1,300,000
Carrying value	1,300,000	1,300,000
Senior notes
Debt Instrument [Line Items]
Debt issued	775,000
Carrying value	794,408	796,138
Senior credit facility
Debt Instrument [Line Items]
Debt issued	511,436
Carrying value	511,436	512,666
Wells Fargo note payable
Debt Instrument [Line Items]
Debt issued	6,773
Carrying value	$ 6,773	$ 7,066

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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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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