Schedule IV - Mortgage Loans on Real Estate (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022		Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens		$ 63,740
Face Amount of Mortgages		10,175
Carrying Amount of Mortgages		9,456	[1]	$ 9,543	$ 39,892
Principal Amount of Loans Subject to delinquent Principal or Interest		0
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Other Disclosure [Abstract]
Aggregate tax basis for Federal tax purposes		10,100
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at beginning of year		9,543		39,892	30,429
January 1, 2020 adoption of new accounting standard					(790)
Acquisitions of loans, net of valuation adjustements					9,560
Issuance of loans				600	693
Collection and satisfaction of loans		(43)		(30,339)
Valuation adjustments		(44)		(610)
Balance at end of year		9,456	[1]	$ 9,543	$ 39,892
Second Mortgage on a retail shopping center in Rockville, MD One
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	[2]	58,750
Face Amount of Mortgages		5,075
Carrying Amount of Mortgages	[1]	4,956
Principal Amount of Loans Subject to delinquent Principal or Interest		0
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at end of year	[1]	4,956
Second Mortgage on a retail shopping center in Rockville, MD Two
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens	[2]	58,750
Face Amount of Mortgages		4,500
Carrying Amount of Mortgages	[1]	4,500
Principal Amount of Loans Subject to delinquent Principal or Interest		0
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at end of year	[1]	$ 4,500
Second mortgage on a retail shopping center in Baltimore, MD
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate		7.00%
Prior Liens	[3]	$ 4,990
Face Amount of Mortgages		600
Carrying Amount of Mortgages	[1]	0
Principal Amount of Loans Subject to delinquent Principal or Interest		0
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at end of year	[1]	$ 0
Interest Rate One | Second Mortgage on a retail shopping center in Rockville, MD One
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate		11.50%
Interest Rate Two | Second Mortgage on a retail shopping center in Rockville, MD Two
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest Rate		10.75%

[1] The amounts are net of any expected losses in accordance with ASU 2016-13. See note 2 to the consolidated financial statements. For Federal tax purposes, the aggregate tax basis is approximately $10.1 million as of December 31, 2022.

[2] These mortgages are both subordinate to a first mortgage of $58.8 million in total. We do not hold the first mortgage loan on this property. Accordingly, the amount of the prior lien at December 31, 2022 is estimated.

[3] This mortgage is subordinate to a first mortgage of $5.0 million. We do not hold the first mortgage loan on this property. Accordingly, the amount of the prior lien at December 31, 2022 is estimated.