Significant Accounting Policies All Other - Quarterly (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Assets	$ 10,943,641	$ 7,828,199
Liabilities	9,699,564	6,659,078
Variable Interest Entity, Primary Beneficiary [Member]
Assets	303,500	325,500
Liabilities	$ 7,700	$ 10,100
Operating Company | Hedge Funds
Asset Management Fees, Percent Fee	2.00%
Operating Company | During investment period | Minimum
Asset Management Fees, Percent Fee	1.00%
Operating Company | During investment period | Maximum
Asset Management Fees, Percent Fee	2.00%
Operating Company | During investment period | Other Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee	0.20%
Operating Company | During investment period | Other Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee	1.00%
Operating Company | After investment period | Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee	1.00%
Operating Company | After investment period | Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee	2.00%