Mortgage Notes Receivable - Composition of loan portfolio (Details) - USD ($) $ in Thousands		Jun. 30, 2022		Mar. 31, 2022		Dec. 31, 2021		Jun. 30, 2021	Mar. 31, 2021		Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 966,752				$ 911,744
CECL Allowance		(9,526)	[1]	$ (8,647)		(10,394)	[2]	$ (10,943)	$ (10,663)		$ (10,590)
Carrying value, net		$ 957,226				$ 901,350
Percentage of portfolio		100.00%				100.00%
2022		$ 345,615	[3]			$ 597,269	[4]
2021		475,017	[3]			239,739	[4]
2020		104,848	[3]			3,102	[4]
2019		3,522	[3]			6,099	[4]
2018		1,296	[3]			65,274	[4]
Prior		$ 36,454	[3]			$ 261	[4]
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		$ 34,963	[5]			$ 53,907
Percentage of portfolio		3.60%	[5]			5.90%
2022		$ 5,077	[5],[6]			$ 32,634	[7]
2021	[5],[6]	29,886
2019	[7]					3,608
2018		0	[5],[6]			17,665	[7]
Prior		0	[5],[6]			0	[7]
41 - 45%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 45,971	[5]			$ 48,431	[8]
Percentage of portfolio		4.80%	[5]			5.30%	[8]
2022		$ 14,769	[5],[6]			$ 44,380	[7],[8]
2021		29,329	[5],[6]			4,051	[7],[8]
2020	[5],[6]	1,873
46 - 50%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 47,033	[5]			$ 63,690	[8]
Percentage of portfolio		4.90%	[5]			7.00%	[8]
2022		$ 17,475	[5],[6]			$ 41,356	[7],[8]
2021		13,424	[5],[6]			21,317	[7],[8]
2020	[5],[6]	16,134
2019	[7],[8]					1,017
Prior	[7],[8]					0
51 - 55%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 130,342	[5]			$ 92,238	[8]
Percentage of portfolio		13.50%	[5]			10.10%	[8]
2022		$ 54,426	[5],[6]			$ 74,978	[7],[8]
2021		66,778	[5],[6]			17,260	[7],[8]
2020	[5],[6]	8,776
Prior	[5],[6]	362
56 - 60%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 99,739	[5]			$ 79,039	[8]
Percentage of portfolio		10.30%	[5]			8.70%	[8]
2022		$ 67,971	[5],[6]			$ 27,115	[7],[8]
2021		31,319	[5],[6]			40,190	[7],[8]
2020	[5],[6]	449
2018	[7],[8]					11,473
Prior	[7],[8]					261
61 - 65%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 543,820	[5]			$ 559,997	[8]
Percentage of portfolio		56.30%	[5]			61.40%	[8]
2022		$ 142,917	[5],[6]			$ 372,645	[7],[8]
2021		302,052	[5],[6]			146,640	[7],[8]
2020		57,941	[5],[6]			3,102	[7],[8]
2019		3,522	[5],[6]			1,474	[7],[8]
2018		1,296	[5],[6]			36,136	[7],[8]
Prior	[5],[6]	36,092
66 - 70%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 41,067	[5]			$ 645	[8]
Percentage of portfolio		4.20%	[5]			0.10%	[8]
2022		$ 39,736	[5],[6]			$ 645	[7],[8]
2021	[5],[6]	$ 1,331
71-80%
Loans and Leases Receivable Disclosure [Line Items]
Percentage of portfolio		0.20%				0.00%	[8]
71 - 75%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 1,092
Percentage of portfolio		0.10%
2022		$ 1,092
76 - 80%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		2,152
2022		2,152
Above 80%
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		20,573	[5]			$ 13,797	[8]
CECL Allowance		$ (9,526)	[9]			$ (10,394)	[10]
Percentage of portfolio		2.10%	[5]			1.50%	[8]
2022	[7],[8]					$ 3,516
2021		$ 898	[5],[6]			10,281	[7],[8]
2020	[5],[6]	19,675
Apartments
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 140,899				$ 107,765
Percentage of portfolio		14.60%				11.80%
2022		$ 76,665	[11]			$ 38,232
2021		37,709	[11]			68,356	[12]
2020	[11]	24,943
2019		1,582	[11]			1,177	[12]
2018	[11]	0
Prior	[3]	0
Residential Lots
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 134,405				$ 111,644
Percentage of portfolio		13.90%				12.20%
2022		$ 40,296	[11]			$ 85,219
2021		75,947	[11]			26,425	[12]
2020	[11]	18,162
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Single family housing
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 116,164				$ 87,902
Percentage of portfolio		12.10%				9.60%
2022		$ 72,439	[11]			$ 84,703
2021		41,382	[11]			3,049	[12]
2020	[11]	2,343
2019	[11]	0
2018		0	[11]			150	[12]
Prior	[3]	0
Townhomes
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 99,851				$ 93,300
Percentage of portfolio		10.30%				10.20%
2022		$ 52,180	[11]			$ 51,240
2021		46,067	[11]			28,979	[12]
2020	[11]	1,242
2019		0	[11]			1,017	[12]
2018		0	[11]			11,803	[12]
Prior		362	[3]			261	[12]
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 71,457				$ 61,592
Percentage of portfolio		7.40%				6.80%
2022		$ 7,489	[11]			$ 61,592
2021	[11]	63,968
2020	[11]	0
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Mixed Use
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 73,109				$ 85,929
Percentage of portfolio		7.60%				9.50%
2022		$ 4,434	[11]			$ 53,530
2021		57,025	[11]			30,474	[12]
2020		9,710	[11]			1,925	[12]
2019	[11]	1,940
2018	[11]	0
Prior		0	[3]			0	[12]
Condos
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 70,526				$ 64,492
Percentage of portfolio		7.30%				7.10%
2022		$ 2,759	[11]			$ 8,805
2021		7,130	[11]			18,227	[12]
2020	[11]	23,249
2019		0	[11]			1,474	[12]
2018		1,296	[11]			35,986	[12]
Prior		36,092	[3]			0	[12]
Senior Housing
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 14,306				$ 61,236
Percentage of portfolio		1.50%				6.70%
2022		$ 0	[11]			$ 35,899
2021		14,306	[11]			25,337	[12]
2020	[11]	0
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Storage
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 56,730				$ 56,481
Percentage of portfolio		5.90%				6.20%
2022						$ 56,481
2021		$ 56,730
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Unentitled Land
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 43,329				$ 46,019
Percentage of portfolio		4.50%				5.00%
2022		$ 32,912	[11]			$ 42,411
2021	[11]	10,417
2020	[11]	0
2019	[11]	0
2018		0	[11]			3,608	[12]
Prior	[3]	0
Entitled Land
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 46,070				$ 45,098
Percentage of portfolio		4.80%				4.90%
2022		$ 18,765	[11]			$ 27,763
2021	[11]	27,305
2020	[11]	0
2019	[11]	0
2018		0	[11]			17,335	[12]
Prior	[3]	0
Hotel
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 29,839				$ 31,665
Percentage of portfolio		3.10%				3.50%
2022		$ 13,926	[11]			$ 4,886
2021		0	[11]			26,779	[12]
2020	[11]	15,913
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Offices
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 18,581				$ 15,348
Percentage of portfolio		1.90%				1.70%
2022		$ 0	[11]			$ 8,280
2021		10,783	[11]			7,068	[12]
2020	[11]	7,798
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Quadplex
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 12,680				$ 9,769
Percentage of portfolio		1.30%				1.10%
2022		$ 6,211	[11]			$ 9,769
2021	[11]	6,469
2020	[11]	0
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Commercial Lots
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 9,340				$ 10,227
Percentage of portfolio		1.00%				1.10%
2022		$ 2,376	[11]			$ 6,670
2021	[11]	6,964
2020		0	[11]			3,557	[12]
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Commercial other
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 11,092				$ 9,080
Percentage of portfolio		1.10%				1.00%
2022		$ 0	[11]			$ 9,080
2021		11,092	[11]			0	[12]
2020	[11]	0
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Retail
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 8,422				$ 7,873
Percentage of portfolio		0.90%				0.90%
2022		$ 5,211				$ 6,385
2021	[11]	1,723
2020		1,488	[11]			1,488	[12]
2019		0	[11]			0	[12]
2018	[11]	0
Prior	[3]	0
Duplex
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 8,894				$ 6,324
Percentage of portfolio		0.90%				0.70%
2022		$ 8,894	[11]			$ 6,324
2021	[11]	0
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Triplex
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 1,058
Percentage of portfolio		0.10%
2022	[11]	$ 1,058
2021	[11]	0
2020	[11]	0
2019	[11]	0
2018	[11]	0
Prior	[3]	0
Vertical Construction
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 490,054				$ 478,475
Percentage of portfolio		50.70%				52.50%
2022		$ 189,305	[3]			$ 234,861	[4]
2021		184,441	[3]			191,896	[4]
2020		76,976	[3]			1,177	[4]
2019		1,582	[3]			2,491	[4]
2018		1,296	[3]			47,789	[4]
Prior		36,454	[3]			261	[4]
Horizontal Development
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 242,332				$ 196,543
Percentage of portfolio		25.20%				21.50%
2022		$ 92,490	[3]			$ 169,041	[4]
2021		131,680	[3]			27,502	[4]
2020		18,162	[3]			0	[4]
2019		0	[3]			0	[4]
2018		0	[3]			0	[4]
Prior	[4]					0
Acquisition
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 108,277				$ 96,937
Percentage of portfolio		11.20%				10.60%
2022		$ 12,247	[3]			$ 96,937	[4]
2021		96,030	[3]			0	[4]
2020		0	[3]			0	[4]
2019		0	[3]			0	[4]
2018		0	[3]			0	[4]
Prior		0	[3]			0	[4]
Investment
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 51,984				$ 65,703
Percentage of portfolio		5.40%				7.20%
2022		$ 37,336	[3]			$ 42,509	[4]
2021		14,648	[3]			2,101	[4]
2020		0	[3]			0	[4]
2019		0	[3]			3,608	[4]
2018		0	[3]			17,485	[4]
Prior		0	[3]			0	[4]
Rehabilitation
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 33,036				$ 27,023
Percentage of portfolio		3.40%				3.00%
2022		$ 12,480	[3]			$ 11,320	[4]
2021		10,846	[3]			15,703	[4]
2020		9,710	[3]			0	[4]
2019		0	[3]			0	[4]
2018		0	[3]			0	[4]
Prior		0	[3]			0	[4]
Land Entitlement
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 25,691				$ 24,529
Percentage of portfolio		2.70%				2.70%
2022		$ 1,757	[3]			$ 24,529	[4]
2021		23,934	[3]			0	[4]
2020		0	[3]			0	[4]
2019		0	[3]			0	[4]
2018		0	[3]			0	[4]
Prior		0	[3]			0	[4]
Bridge
Loans and Leases Receivable Disclosure [Line Items]
Carrying Value		$ 15,378				$ 22,534
Percentage of portfolio		1.60%				2.50%
2022		$ 0	[3]			$ 18,072	[4]
2021		13,438	[3]			2,537	[4]
2020		0	[3]			1,925	[4]
2019		1,940	[3]			0	[4]
2018		0	[3]			0	[4]
Prior		0	[3]			0	[4]
Unfunded Loan Commitment [Member]
Loans and Leases Receivable Disclosure [Line Items]
CECL Allowance		(1,410)		$ (1,097)	[13]	$ (904)	[13]	$ (725)	$ (947)	[13]	$ 0	[13]
Unfunded Loan Commitment [Member] | Accounts payable and accrued liabilities
Loans and Leases Receivable Disclosure [Line Items]
CECL Allowance		(1,400)
Allowances on excess amortized cost over fair value		$ 1,000

[1] Includes $1.0 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, $1.4 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.

[2] 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.

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

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

[5] 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.

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

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

[8] 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.

[9] Includes $1.0 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, $1.4 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.

[10] 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.

[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 condensed consolidated balance sheet.