Investment in Convertible Notes (Details) - USD ($)			3 Months Ended				9 Months Ended
	Oct. 11, 2019	Jul. 19, 2019	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 30, 2021	Mar. 09, 2021	Jul. 30, 2020
Debt Securities, Available-for-sale [Line Items]
Monthly installment receivable	$ 1,000,000
Unrealized gain (loss) on investments in convertible notes			$ (315,000)	$ 5,204,000	$ 469,000	$ 0	$ 5,358,000	$ 0
Convertible Promissory Notes
Debt Securities, Available-for-sale [Line Items]
Investment purchase	$ 25,000,000.0	$ 30,000,000.0							$ 30,000,000	$ 25,000,000	$ 25,000,000
Investment interest rate		3.00%
Investment owned, fair value, including accrued interest									$ 39,300,000
Convertible Promissory Notes | Subordinated Debt
Debt Securities, Available-for-sale [Line Items]
Investment purchase		$ 5,000,000.0								$ 5,000,000	$ 5,000,000
Investment maturity		6 months