Significant Accounting Policies - Investment in Marketable Securities (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($) security	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) security	Sep. 30, 2021 USD ($) security	Dec. 31, 2021 USD ($) security
Investment in Marketable Securities
Total marketable securities available-for-sale	$ 12,039,000		$ 12,039,000		$ 24,146,000
Equity marketable securities	4,496,000		4,496,000		10,606,000
Total investment in marketable securities	16,535,000		16,535,000		34,752,000
Marketable securities, unrealized gain (loss)	100,000	$ 2,000,000	(6,100,000)	$ 100,000
Amount of disposal of equity marketable securities	0		0
Proceeds from sale of marketable securities	7,800,000	$ 0	7,800,000
Proceeds from repayment of debt marketable securities	$ 3,700,000		$ 3,700,000	$ 4,500,000
Number of marketable securities sold | security	1		1
Number of marketable securities repaid | security	1		1	1
Commercial mortgage-backed securities
Investment in Marketable Securities
Total marketable securities available-for-sale	$ 12,039,000		$ 12,039,000		24,146,000
Cost basis of commercial mortgage-backed securities	$ 11,500,000		$ 11,500,000		$ 23,000,000
Number of securities in continuous unrealized loss position | security					1
Unrealized loss					$ 600,000
Fair value of security in a continuous unrealized loss position for less than 12 months					$ 7,200,000