Debt - (Summary of Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Outstanding Principal	$ 2,593,981
Deferred financing costs	(7,846)	$ (8,491)
Total debt	2,606,414	2,607,379
Debt classified as current, net of deferred financing costs	(3,085)	(3,008)
Total long-term debt	2,603,329	2,604,371
Margin Loan Facility
Debt Instrument [Line Items]
Outstanding Principal	1,300,000
Carrying value	1,300,000	1,300,000
Senior notes
Debt Instrument [Line Items]
Outstanding Principal	775,000
Carrying value	795,279	796,138
Senior credit facility
Debt Instrument [Line Items]
Outstanding Principal	512,051
Carrying value	512,051	512,666
Wells Fargo note payable
Debt Instrument [Line Items]
Outstanding Principal	6,930
Carrying value	$ 6,930	$ 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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