Mortgage Notes Receivable - Composition of loan portfolio (Details) - USD ($) $ in Thousands		Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 923,442	[1]	$ 911,744	[2]
CECL Allowance		(41,492)	[1],[3],[4]	(10,394)	[2],[5],[6]
Carrying value, net		$ 881,950	[1]	$ 901,350	[2]
Percentage of portfolio		100.00%	[1]	100.00%	[2]
2022		$ 592,959	[1],[7],[8],[9]	$ 597,269	[2],[10]
2021		236,004	[1],[7],[8],[9]	239,739	[2],[10]
2020		54,167	[1],[7],[8],[9]	3,102	[2],[10]
2019		4,152	[1],[7],[8],[9]	6,099	[2],[10]
2018	[2],[10]			65,274
Prior		$ 36,160	[1],[4],[9]	$ 261	[2],[10]
LTV general percent indicating default status		65		65
Allowances on excess amortized cost over fair value				$ 700
0 - 40%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 26,053	[1]	$ 53,907	[2]
Percentage of portfolio		2.80%	[1]	5.90%	[2]
2022		$ 22,544	[1],[8]	$ 32,634	[2],[11]
2021	[1],[8]	3,509
2019	[2],[11]			3,608
2018	[2],[11]			17,665
Prior	[2],[11]			0
41 - 45%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 29,025	[1]	$ 48,431	[2]
Percentage of portfolio		3.10%	[1]	5.30%	[2]
2022		$ 7,039	[1],[8]	$ 44,380	[2],[11]
2021		21,986	[1],[8]	4,051	[2],[11]
2020	[1],[8]	0
2019	[2],[11]			0
46 - 50%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 42,267	[1]	$ 63,690	[2]
Percentage of portfolio		4.60%	[1]	7.00%	[2]
2022		$ 22,524	[1],[8]	$ 41,356	[2],[11]
2021		13,455	[1],[8]	21,317	[2],[11]
2020	[1],[8]	6,288
2019	[2],[11]			1,017
Prior	[2],[11]			0
51 - 55%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 144,649	[1]	$ 92,238	[2]
Percentage of portfolio		15.70%	[1]	10.10%	[2]
2022		$ 76,978	[1],[8]	$ 74,978	[2],[11]
2021		58,876	[1],[8]	17,260	[2],[11]
2020	[1],[8]	8,795
2018	[2],[11]			0
56 - 60%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 107,098	[1]	$ 79,039	[2]
Percentage of portfolio		11.60%	[1]	8.70%	[2]
2022		$ 98,691	[1],[8]	$ 27,115	[2],[11]
2021		8,407	[1],[8]	40,190	[2],[11]
2020		0	[1],[8]	0	[2],[11]
2019	[1],[8]	0
2018	[2],[11]			11,473
Prior	[2],[11]			261
61 - 65%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 456,743	[1]	$ 559,997	[2]
Percentage of portfolio		49.50%	[1]	61.40%	[2]
2022		$ 284,722	[1],[8]	$ 372,645	[2],[11]
2021		112,569	[1],[8]	146,640	[2],[11]
2020		21,364	[1],[8]	3,102	[2],[11]
2019		1,928	[1],[8]	1,474	[2],[11]
2018	[2],[11]			36,136
Prior	[1],[8]	36,160
66 - 70%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 93,104	[1]	$ 645	[2]
Percentage of portfolio		10.10%	[1]	0.10%	[2]
2022		$ 71,638	[1],[8]	$ 645	[2],[11]
2021	[1],[8]	16,561
2020	[1],[8]	2,681
2019	[1],[8]	2,224
71 - 75%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value	[1]	$ 4,280
Percentage of portfolio	[1]	0.50%
2022	[1],[8]	$ 4,280
2021	[8]	0
2020	[8]	0
2019	[8]	0
Prior	[8]	0
71 - 80%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value	[2]			$ 0
Percentage of portfolio	[2]			0.00%
2022	[2],[11]			$ 0
76 - 80%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value	[1]	$ 2,540
Percentage of portfolio	[1]	0.30%
2022	[1],[8]	$ 2,540
2021	[8]	0
2020	[8]	0
2019	[8]	0
Prior	[8]	0
Above 80%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 17,683	[1]	$ 13,797	[2]
Percentage of portfolio		1.90%	[1]	1.50%	[2]
2022		$ 2,003	[8]	$ 3,516	[2],[11]
2021		641	[1],[8]	10,281	[2],[11]
2020		15,039	[1],[8]	0	[2],[11]
2018	[2],[11]			0
Prior	[8]	0
Apartments
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 191,708		$ 107,765
Percentage of portfolio		20.80%		11.80%
2022		$ 134,816	[7]	$ 38,232	[12]
2021		49,944	[7]	68,356	[12]
2020		5,020	[7]	1,177	[12]
2019		1,928	[7]	0	[12]
2018	[12]			0
Prior	[4]	0
Residential Lots
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 104,100		$ 111,644
Percentage of portfolio		11.30%		12.20%
2022		$ 56,675	[4]	$ 85,219	[12]
2021		38,630	[4]	26,425	[12]
2020	[4]	8,795
2019	[4]	0
2018	[12]			0
Prior	[4]	0
Single Family Housing
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 133,702		$ 87,902
Percentage of portfolio		14.50%		9.60%
2022		$ 124,218	[4]	$ 84,703	[12]
2021		9,245	[4]	3,049	[12]
2020		239	[4]	0	[12]
2019		0	[4]	0	[12]
2018	[12]			150
Prior		0	[4]	0	[12]
Townhomes
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 106,888		$ 93,300
Percentage of portfolio		11.60%		10.20%
2022		$ 81,393	[4]	$ 51,240	[12]
2021		24,701	[4]	28,979	[12]
2020		794	[4]	0	[12]
2019		0	[4]	1,017	[12]
2018	[12]			11,803
Prior		0	[4]	261	[12]
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 58,515		$ 61,592
Percentage of portfolio		6.30%		6.80%
2022		$ 13,838	[4]	$ 61,592	[12]
2021		44,677	[4]	0	[12]
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Entitled Land
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 76,251		$ 45,098
Percentage of portfolio		8.30%		4.90%
2022		$ 54,265	[4]	$ 27,763	[12]
2021	[4]	21,986
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Condos
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 71,975		$ 64,492
Percentage of portfolio		7.80%		7.10%
2022		$ 29,738	[4]	$ 8,805	[12]
2021		2,515	[4]	18,227	[12]
2020		3,562	[4]	0	[12]
2019		0	[4]	1,474	[12]
2018	[12]			35,986
Prior	[4]	36,160
Mixed Use
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 50,127		$ 85,929
Percentage of portfolio		5.40%		9.50%
2022		$ 6,209	[4]	$ 53,530	[12]
2021		30,217	[4]	30,474	[12]
2020		11,477	[4]	1,925	[12]
2019	[4]	2,224
Prior	[4]	0
Hotel
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 30,221		$ 31,665
Percentage of portfolio		3.30%		3.50%
2022		$ 14,116	[4]	$ 4,886	[12]
2021		0	[4]	26,779	[12]
2020	[4]	16,105
2019	[4]	0
Prior	[4]	0
Unentitled Land
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 17,262		$ 46,019
Percentage of portfolio		1.90%		5.00%
2022		$ 16,325	[4]	$ 42,411	[12]
2021	[4]	937
2020		0	[4]	0	[12]
2019		0	[4]	3,608	[12]
Prior		0	[4]	0	[12]
Offices
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 18,467		$ 15,348
Percentage of portfolio		2.00%		1.70%
2022		$ 12,179	[4]	$ 8,280	[12]
2021		0	[4]	7,068	[12]
2020	[4]	6,288
2019	[4]	0
Prior	[4]	0
Senior Housing
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 16,595		$ 61,236
Percentage of portfolio		1.80%		6.70%
2022		$ 16,595	[4]	$ 35,899	[12]
2021		0	[4]	25,337	[12]
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Commercial other
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 11,411		$ 9,080
Percentage of portfolio		1.20%		1.00%
2022		$ 0	[4]	$ 9,080	[12]
2021	[4]	11,411
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Duplex
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 13,639		$ 6,324
Percentage of portfolio		1.50%		0.70%
2022		$ 13,639	[4]	$ 6,324	[12]
2021	[4]	0
2020	[4]	0
2019		0	[4]	0	[12]
Prior	[4]	0
Retail
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 9,071		$ 7,873
Percentage of portfolio		1.00%		0.90%
2022		$ 5,443	[4]	$ 6,385	[12]
2021		1,741	[4]	1,488	[12]
2020	[4]	1,887
2019	[4]	0
Prior	[4]	0
Quadplex
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 8,932		$ 9,769
Percentage of portfolio		1.00%		1.10%
2022		$ 8,932	[4]	$ 9,769	[12]
2021	[4]	0
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Commercial Lots
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 4,018		$ 10,227
Percentage of portfolio		0.40%		1.10%
2022		$ 4,018	[4]	$ 6,670	[12]
2021		0	[4]	3,557	[12]
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Triplex
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 560
Percentage of portfolio		0.10%
2022	[4]	$ 560
2021	[4]	0
2020	[4]	0
2019	[4]	0
Prior	[4]	0
Storage
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value				$ 56,481
Percentage of portfolio				6.20%
2022	[12]			$ 56,481
Vertical Construction
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 552,468		$ 478,475
Percentage of portfolio		59.80%		52.50%
2022		$ 352,355	[9]	$ 234,861	[10]
2021		128,130	[9]	191,896	[10]
2020		33,895	[9]	1,177	[10]
2019		1,928	[9]	2,491	[10]
2018	[10]			47,789
Prior		36,160	[9]	261	[10]
Horizontal Development
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 221,078		$ 196,543
Percentage of portfolio		24.10%		21.50%
2022		$ 144,082	[9]	$ 169,041	[10]
2021		68,201	[9]	27,502	[10]
2020	[9]	8,795
2019		0	[9]	0	[10]
2018	[10]			0
Prior	[9]	0
Acquisition
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 15,195		$ 96,937
Percentage of portfolio		1.60%		10.60%
2022		$ 13,454	[9]	$ 96,937	[10]
2021	[9]	1,741
2019	[9]	0
Prior	[9]	0
Investment
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 46,536		$ 65,703
Percentage of portfolio		5.00%		7.20%
2022		$ 46,536	[9]	$ 42,509	[10]
2021		0	[9]	2,101	[10]
2020	[10]			0
2019		0	[9]	3,608	[10]
2018	[10]			17,485
Prior		0	[9]	0	[10]
Rehabilitation
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 39,422		$ 27,023
Percentage of portfolio		4.30%		3.00%
2022		$ 12,936	[9]	$ 11,320	[10]
2021		15,009	[9]	15,703	[10]
2020	[9]	11,477
2019	[9]	0
Prior	[9]	0
Land Entitlement
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 26,132		$ 24,529
Percentage of portfolio		2.80%		2.70%
2022		$ 4,146	[9]	$ 24,529	[10]
2021	[9]	21,986
2019	[9]	0
2018	[12]			17,335
Prior	[9]	0
Bridge
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 22,611		$ 22,534
Percentage of portfolio		2.40%		2.50%
2022		$ 19,450	[9]	$ 18,072	[10]
2021		937	[9]	2,537	[10]
2020	[10]			1,925
2019	[9]	2,224
Prior	[9]	0
Unfunded Loan Commitment [Member]
Loans and Leases Receivable Disclosure [Line Items]
CECL Allowance	[13]	(1,474)		(904)		$ 0
Unfunded Loan Commitment [Member] | Accounts payable and accrued liabilities
Loans and Leases Receivable Disclosure [Line Items]
CECL Allowance		(1,500)		$ (900)
Allowances on excess amortized cost over fair value		$ 35,000

[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 $35.0 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, $1.5 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 consolidated balance sheet.

[4] Represents the year of either origination or amendment where the loan incurred a full re-underwriting in connection with the amendment.

[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 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 consolidated balance sheet.

[7] Includes $35.0 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, $1.5 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 consolidated balance sheet.

[8] Represents the year of either origination or amendment where the loan incurred a full re-underwriting in connection with the amendment.

[9] Represents the year of either origination or amendment where the loan incurred a full re-underwriting in connection with the amendment

[10] Represents the year of either origination or amendment where the loan incurred a full re-underwriting in connection with the amendment.

[11] Represents the year of either origination or amendment where the loan incurred a full re-underwriting in connection with the amendment.

[12] Represents the year of either origination or amendment where the loan incurred a full re-underwriting in connection with the amendment.

[13] CECL allowance related to unfunded commitments is presented as a liability under accounts payable and accrued liabilities in our consolidated balance sheet.