Mortgage Notes Receivable - Schedule of carrying value of collateral dependent loans (Details) - USD ($) $ in Thousands		Sep. 30, 2022		Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021		Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 931,661	[1]			$ 911,744	[2]
CECL Allowance		(19,997)	[3],[4]	$ (9,526)	$ (8,647)	(10,394)	[5],[6]	$ (12,719)	$ (10,943)	$ (10,663)	$ (10,590)
Financing Receivable, after Allowance for Credit Loss, Total		911,664				901,350
Allowances on excess amortized cost over fair value						700
Financing Receivable, Allowance for Credit Loss		19,997	[3],[4]	$ 9,526	$ 8,647	10,394	[5],[6]	$ 12,719	$ 10,943	$ 10,663	$ 10,590
Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		83,782				45,772
CECL Allowance		(12,899)	[7]			(1,834)	[8]
Financing Receivable, after Allowance for Credit Loss, Total		70,883				43,938
Allowances on excess amortized cost over fair value		12,100				700
Financing Receivable, Allowance for Credit Loss		12,899	[7]			1,834	[8]
Senior Housing [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		15,538				61,236
Senior Housing [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		34,276				25,337
CECL Allowance		(2,242)	[7]			(1,103)	[8]
Financing Receivable, after Allowance for Credit Loss, Total		32,034				24,234
Financing Receivable, Allowance for Credit Loss		2,242	[7]			1,103	[8]
Apartments
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		169,067				107,765
Entitled Land [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		75,103				45,098
Entitled Land [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value						17,335
CECL Allowance	[8]					(42)
Financing Receivable, after Allowance for Credit Loss, Total						17,293
Financing Receivable, Allowance for Credit Loss	[8]					42
Single Family Housing [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		3,761				1,730
CECL Allowance		(18)	[4]			(15)	[8]
Financing Receivable, after Allowance for Credit Loss, Total		3,743				1,715
Financing Receivable, Allowance for Credit Loss		18	[4]			15	[8]
Condos [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		63,690				64,492
Condos [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		10,075				1,109
CECL Allowance		(917)	[7]			(673)	[8]
Financing Receivable, after Allowance for Credit Loss, Total		9,158				436
Financing Receivable, Allowance for Credit Loss		917	[7]			673	[8]
Townhomes [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		107,515				93,300
Townhomes [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		3,945				261
CECL Allowance		(29)	[7]			(1)	[8]
Financing Receivable, after Allowance for Credit Loss, Total		3,916				260
Financing Receivable, Allowance for Credit Loss		29	[7]			1	[8]
Hotel [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		16,029
CECL Allowance	[4]	(9,113)
Financing Receivable, after Allowance for Credit Loss, Total		6,916
Financing Receivable, Allowance for Credit Loss	[4]	9,113
Commercial Other [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		12,845				9,080
Commercial Other [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		2,997
CECL Allowance	[4]	(38)
Financing Receivable, after Allowance for Credit Loss, Total		2,959
Financing Receivable, Allowance for Credit Loss	[4]	38
Mixed Use [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		53,409				85,929
Mixed Use [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		2,764
CECL Allowance	[4]	(408)
Financing Receivable, after Allowance for Credit Loss, Total		2,356
Financing Receivable, Allowance for Credit Loss	[4]	408
Retail [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		8,818				7,873
Retail [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		1,857
CECL Allowance	[4]	(58)
Financing Receivable, after Allowance for Credit Loss, Total		1,799
Financing Receivable, Allowance for Credit Loss	[4]	58
Offices [Member] | Loan portfolio [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		8,078
CECL Allowance	[3]	(76)
Financing Receivable, after Allowance for Credit Loss, Total		8,002
Financing Receivable, Allowance for Credit Loss	[3]	76
Residential Lots [Member]
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 123,055				$ 111,644

[1] Represents LTV as of origination or latest amendment. LTVs above 65% generally represent loans in contractual default status where we have agreed to extend funds to the borrower above 65% in order to facilitate successful completion of the construction and return of capital.

[2] Represents LTV as of origination or latest amendment. LTVs above 65% generally represent loans in contractual default status where we have agreed to extend funds to the borrower above 65% in order to ensure successful completion of the construction and return of capital.

[3] Includes $12.1 million in loan specific allowances for loans deemed collateral dependent based on the excess amortized cost over the fair value of the underlying collateral. In addition, $1.4 million of the CECL allowance is excluded from this table because it relates to unfunded commitments and has been recorded as a liability under accounts payable and accrued liabilities in our condensed consolidated balance sheet.

[4] Includes $12.1 million in loan specific allowances for loans deemed collateral dependent based on the excess amortized cost over the fair value of the underlying collateral. In addition, $1.4 million of the CECL allowance is excluded from this table because it relates to unfunded commitments and has been recorded as a liability under accounts payable and accrued liabilities in our condensed consolidated balance sheet.       September 30, 2022     Year Originated (1)   (dollars in thousands)   Carrying Value     % of Portfolio     2022     2021     2020     2019     2018     Prior   Collateral Type                                                 Apartments   $ 169,067       18.1 %   $ 111,941     $ 39,609     $ 15,614     $ 1,903     $ —     $ —   Residential lots     123,055       13.2 %     49,947       64,317       8,791       —       —       —   Single Family Housing     121,810       13.1 %     112,919       8,659       232       —       —       —   Townhomes     107,515       11.5 %     80,277       26,445       793       —       —       —   Commercial     87,779       9.4 %     12,750       75,029       —       —       —       —   Entitled Land     75,103       8.1 %     46,741       28,362       —       —       —       —   Condos     63,690       6.8 %     10,900       6,579       10,075       —       —       36,136   Mixed Use     53,409       5.7 %     10,288       29,859       11,133       2,129       —       —   Hotel     30,036       3.2 %     14,007       —       16,029       —       —       —   Unentitled Land     19,981       2.1 %     16,621       3,360       —       —       —       —   Offices     19,372       2.1 %     11,294       —       8,078       —       —       —   Senior Housing     15,538       1.7 %     —       15,538       —       —       —       —   Commercial other     12,845       1.4 %     —       12,845       —       —       —       —   Duplex     11,089       1.2 %     11,089       —       —       —       —       —   Retail     8,818       0.9 %     6,961       —       1,857       —       —       —   Quadplex     7,664       0.8 %     —       7,664       —       —       —       —   Commercial Lots     3,196       0.3 %     3,196       —       —       —       —       —   Triplex     1,694       0.2 %     1,694       —       —       —       —       —   Storage     —       0.0 %     —       —       —       —       —       —   Total   $ 931,661       100.0 %   $ 500,625     $ 318,266     $ 72,602     $ 4,032     $ —     $ 36,136   CECL allowance(2)     (19,997 )                                           Carrying value, net   $ 911,664                                            

[5] Includes $0.7 million in loan specific allowances for loans deemed collateral dependent based on the excess amortized cost over the fair value of the underlying collateral. In addition, $0.9 million of the CECL allowance is excluded from this table because it relates to unfunded commitments and has been recorded as a liability under accounts payable and accrued liabilities in our condensed consolidated balance sheet.

[6] Includes $0.7 million in loan specific allowances for loans deemed collateral dependent based on the excess amortized cost over the fair value of the underlying collateral. In addition, $0.9 million of the CECL allowance is excluded from this table because it relates to unfunded commitments and has been recorded as a liability under accounts payable and accrued liabilities in our condensed consolidated balance sheet.

[7] Includes $12.1 million in loan specific allowances for loans deemed collateral dependent based on the excess amortized cost over the fair value of the underlying collateral.

[8] Includes $0.7 million in loan specific allowances for loans deemed collateral dependent based on the excess amortized cost over the fair value of the underlying collateral.