Investing Receivables - Components of Investing Receivables (Details) - Investing Receivables - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 83,889	$ 87,415
Allowance for credit losses	(2,377)	(2,794)	$ (1,599)	$ (2,851)
Investing receivables, net	81,512	84,621
Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	77,022	69,703
Other investing loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 6,867	$ 17,712