Significant Accounting Policies - Investment in Marketable Securities (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) retailAsset security	Dec. 31, 2021 USD ($) security	Dec. 31, 2020 USD ($)
Investment in Marketable Securities
Marketable securities available-for-sale	$ 11,240,000	$ 24,146,000
Equity marketable securities	0	10,606,000
Investments in marketable securities	11,240,000	34,752,000
Proceeds from sale of marketable securities	$ 7,800,000	$ 4,500,000	$ 0
Number of marketable securities sold | security	1	1
Proceeds from the repayment of debt marketable securities	$ 3,700,000
Number of securities repaid | security	1
Number of securities sold | retailAsset	1
Proceeds from sale of equity marketable securities	$ 4,200,000	$ 0
Realized loss	6,500,000
Marketable securities, unrealized gain		600,000
Commercial mortgage-backed securities
Investment in Marketable Securities
Marketable securities available-for-sale	11,240,000	24,146,000
Cost basis of commercial mortgage backed securities	11,500,000	23,000,000
Unrealized loss	300,000	600,000
Fair value of security in a continuous unrealized loss position for less than 12 months	$ 11,200,000	$ 7,200,000
Number of securities in continuous unrealized loss position | security		1