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Agreements and Transactions with Related Parties - Other Related Party (Details) $ in Thousands	1 Months Ended										3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($) item shares	Mar. 31, 2021 USD ($)	Jan. 31, 2021	Dec. 31, 2020 USD ($)	Oct. 31, 2020 USD ($)	Aug. 31, 2020 USD ($)	Mar. 31, 2020 USD ($) property	Sep. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Jun. 30, 2018 USD ($) property loan	Jun. 30, 2021 USD ($) item shares	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) item shares	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) loan property item	Dec. 31, 2016 USD ($) property shares	Dec. 31, 2015 USD ($)	Jul. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)
Agreements and transactions with related parties
Due to related party	$ 6,184			$ 2,365							$ 6,184		$ 6,184
Due from related parties	11,084			12,449							11,084		11,084
Entitled to annual fee	$ 300										$ 300		$ 300
Equity participation interest (as a percentage)	33.00%										33.00%		33.00%
Investment made													$ 2,814,170	$ 1,117,004
Indirect ownership percentage													9.20%
(Income) loss from equity affiliates											$ (4,759)	$ (20,408)	$ (27,010)	(24,401)
Single-Family Rental
Agreements and transactions with related parties
Investment made				3,500
Operating Partnership Units | Special voting preferred shares
Agreements and transactions with related parties
Number of preferred stock shares paired with each OP units | shares													1
Preferred equity investments
Agreements and transactions with related parties
Equity investment	$ 7,800										7,800		$ 7,800
Preferred equity investments | Single-Family Rental
Agreements and transactions with related parties
Investment made					$ 4,600
Bridge loans
Agreements and transactions with related parties
Principal amount	35,000										35,000		35,000
Bridge loans | Single-Family Rental
Agreements and transactions with related parties
Loan committed	1,500			$ 32,500	$ 30,500
Bridge loans | Preferred equity interest financing agreement
Agreements and transactions with related parties
Interest income recorded											300	600	700	1,400
Bridge Loan Several Multifamily Properties [Member]
Agreements and transactions with related parties
Principal amount																$ 37,500
Percentage of ownership interest of related party in the entity																85.00%
Bridge Loan Six Multifamily Properties [Member]
Agreements and transactions with related parties
UPB converted to a mezzanine loan									$ 2,000
Bridge Loan Six Multifamily Properties [Member] | Maturity Date September 2019 [Member]
Agreements and transactions with related parties
Principal amount																		$ 12,900
Lexford Portfolio | Maturity date of March 2030 | Private Label
Agreements and transactions with related parties
Principal amount							$ 34,600
Fixed rate of interest (as a percent)							3.30%
Lexford Portfolio | Bridge loans | Maturity Date Of June 2021 [Member]
Agreements and transactions with related parties
Paydowns of principal made by borrower															$ 250,000
Base spread (as a percent)										4.00%
Unsecured financing provided by an unsecured lender to certain parent entities of the property owners	50,000										50,000		50,000
ACM, Certain executives and Consortium of independent outside investors | Mature date of April 2030 | Private Label
Agreements and transactions with related parties
Principal amount							$ 14,800
Fixed rate of interest (as a percent)							3.10%
ACM, Certain executives and Consortium of independent outside investors | Mezzanine loans | Mature date of April 2030
Agreements and transactions with related parties
Number of properties owned | property							2
Percentage of ownership interest of related party in the entity							50.00%
Interest income recorded											100		100
Equity investment							$ 3,400
Fixed rate of interest (as a percent)							9.00%
ACM, Certain executives and Consortium of independent outside investors | Mezzanine loans | Maturity date of March 2030
Agreements and transactions with related parties
Interest income recorded												200		200
ACM, Certain executives and Consortium of independent outside investors | AMAC III
Agreements and transactions with related parties
Amount invested	$ 15,700										15,700		15,700								$ 30,000
Ownership interest (as a percent)																					18.00%
Interest income recorded											300	700	600	1,600
Loss on investment												500		600
ACM, Certain executives and Consortium of independent outside investors | AMAC III | Private Label
Agreements and transactions with related parties
Percentage of ownership interest of related party in the entity															100.00%
Fixed rate of interest (as a percent)															3.735%
Amount of loan to related party															$ 15,600
ACM / Our "Former Manager" | Residential Mortgage Banking Company
Agreements and transactions with related parties
Interest income recorded											4,800	20,900	27,300	23,800
Noncontrolling interest in equity method investment acquired (as a percent)																			50.00%
Indirect ownership percentage			12.30%																22.50%
Acquisition purchase price																			$ 9,600
Cash distribution received											$ 5,600		$ 18,700
ACM / Our "Former Manager" | ACM Acquisition
Agreements and transactions with related parties
Number of preferred stock shares paired with each OP units | shares																		1
Number of shares held by related party | shares	2,828,629										2,828,629		2,828,629
OP units hold as part of acquisition | shares													10,692,668
Aggregate percentage of voting power held by related party	8.60%										8.60%		8.60%
Consortium of investors including other unaffiliated investors, certain of officers and chief executive officer | Bridge Loan Several Multifamily Properties [Member]
Agreements and transactions with related parties
Principal amount																$ 19,500
Base spread (as a percent)																4.00%
Interest income recorded													$ 600
Consortium of investors including other unaffiliated investors, certain of officers and chief executive officer | Bridge Loan Several Multifamily Properties [Member] | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)																2.125%
Consortium of investors including other unaffiliated investors, certain of officers and chief executive officer | Bridge Loan Several Multifamily Properties [Member] | Multifamily
Agreements and transactions with related parties
Interest income recorded												300
Consortium of investors including other unaffiliated investors, certain of officers and chief executive officer | Bridge Loan One Multifamily Property [Member]
Agreements and transactions with related parties
Principal amount	$ 34,000										$ 34,000		34,000
Consortium of investors including other unaffiliated investors, certain of officers and chief executive officer | Bridge Loan One Multifamily Property [Member] | Maturity Date Of August 2022
Agreements and transactions with related parties
Principal amount	$ 34,000					$ 35,400					34,000		34,000
Consortium of investors including other unaffiliated investors, certain of officers and chief executive officer | Bridge Loan One Multifamily Property [Member] | Maturity Date Of August 2022 | LIBOR
Agreements and transactions with related parties
Variable rate, spread (as a percent)						3.50%
Consortium of investors including an immediate family member of our officers | Multifamily | Fannie Mae
Agreements and transactions with related parties
Percentage of maximum loss-sharing obligation unpaid principal balance																	5.00%
Principal amount																	$ 46,900
Percentage of ownership interest of related party in the entity																	17.60%
Consortium of investors including an immediate family member of our officers | Maximum | Multifamily | Fannie Mae
Agreements and transactions with related parties
Interest income recorded													100
Consortium of investors including an immediate family member of our officers | Bridge Loan Several Multifamily Properties [Member] | Multifamily
Agreements and transactions with related parties
Interest income recorded														600
Consortium of investors including an immediate family member of our officers | Bridge Loan One Multifamily Property [Member]
Agreements and transactions with related parties
Principal amount																				$ 7,000
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Several Multifamily Properties [Member] | Maturity Date Of January 2021 [Member]
Agreements and transactions with related parties
Due to related party																$ 9,400
Percentage of ownership interest of related party in the entity																75.00%
Interest income recorded											100	100	300	300
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Several Multifamily Properties [Member] | Maturity Date Of January 2021 [Member] | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)																5.00%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Several Multifamily Properties [Member] | Maturity Date Of January 2021 [Member] | Minimum | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)																1.25%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan One Multifamily Property [Member] | Maturity Date Of June 2021 [Member]
Agreements and transactions with related parties
Principal amount																$ 21,700
Percentage of ownership interest of related party in the entity																75.00%
Interest income recorded											300	300	700	700
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan One Multifamily Property [Member] | Maturity Date Of June 2021 [Member] | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)																4.75%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan One Multifamily Property [Member] | Maturity Date Of June 2021 [Member] | Minimum | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)																1.25%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Two Multifamily Properties [Member] | Maturity date of October 2021
Agreements and transactions with related parties
Principal amount																	$ 31,100
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Two Multifamily Properties [Member] | Maturity date of October 2021 | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)																	4.00%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Two Multifamily Properties [Member] | Maturity date of October 2021 | Minimum
Agreements and transactions with related parties
Base spread (as a percent)																	1.80%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Two Multifamily Properties [Member] | Maturity Date Of Fourth Quarter 2020 [Member]
Agreements and transactions with related parties
Principal amount																	$ 28,000
Number of properties owned | property																	2
Percentage of ownership interest of related party in the entity																	45.00%
Base spread (as a percent)																	5.25%
Interest income recorded											$ 500	500	$ 1,000	1,000
Number of bridge loans originated | item																	2
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Two Multifamily Properties [Member] | Maturity Date Of Fourth Quarter 2020 [Member] | Minimum
Agreements and transactions with related parties
LIBOR floor (as a percentage)																	1.24%
Certain certain officers, chief executive officer, and other unaffiliated investors | Bridge Loan Two Multifamily Properties [Member] | Maturity Date Of Fourth Quarter 2020 [Member] | Maximum
Agreements and transactions with related parties
LIBOR floor (as a percentage)																	1.54%
Chief executive officer | Minimum
Agreements and transactions with related parties
Ownership interest limit of our common stock under company charter (as a percent)	5.00%										5.00%		5.00%
Mr. Ivan Kaufman
Agreements and transactions with related parties
Percentage of our Former Manager's outstanding membership interest of related party in another related party	35.00%										35.00%		35.00%
Board of Directors
Agreements and transactions with related parties
Number of portfolios of multifamily properties | item	2										2		2
Board of Directors | Ginkgo Investment Company LLC [Member]
Agreements and transactions with related parties
Percentage of managing member																	33.00%
Immediate family member of chief executive officer | Matures in October 2023 [Member] | Preferred equity interest financing agreement
Agreements and transactions with related parties
Interest income recorded											$ 100		$ 200
Immediate family member of chief executive officer | Matures in May 2023 [Member] | Preferred equity interest financing agreement
Agreements and transactions with related parties
Interest income recorded											200		300
Immediate family member of chief executive officer | Preferred equity investments | Matures in October 2023 [Member]
Agreements and transactions with related parties
Fixed rate of interest (as a percent)				12.00%
Immediate family member of chief executive officer | Preferred equity investments | Matures in May 2023 [Member]
Agreements and transactions with related parties
Fixed rate of interest (as a percent)					12.00%
Immediate family member of chief executive officer | Bridge loans
Agreements and transactions with related parties
Equity participation interest (as a percentage)				21.80%	18.90%
Immediate family member of chief executive officer | Bridge loans | Land
Agreements and transactions with related parties
Principal amount																$ 17,700
Paydowns of principal made by borrower								$ 4,700
Percentage of ownership interest of related party in the entity																10.80%
Interest income recorded														100
Fixed rate of interest (as a percent)																10.00%
Immediate family member of chief executive officer | Bridge loans | Matures in October 2023 [Member] | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)				5.50%
LIBOR floor (as a percentage)				0.75%
Immediate family member of chief executive officer | Bridge loans | Matures in May 2023 [Member]
Agreements and transactions with related parties
Base spread (as a percent)					5.50%
LIBOR floor (as a percentage)					0.75%
Immediate family member of chief executive officer | Bridge Loan Several Multifamily Properties [Member]
Agreements and transactions with related parties
Percentage of ownership interest of related party in the entity															23.90%
LIBOR floor (as a percentage)															2.375%
Interest income recorded												800		1,400
Immediate family member of chief executive officer | Bridge Loan Several Multifamily Properties [Member] | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)															4.25%
Lexford Portfolio | Preferred equity investments
Agreements and transactions with related parties
(Income) loss from equity affiliates												$ 200		200
Lexford Portfolio | Bridge loans | Maturity Date Of June 2021 [Member]
Agreements and transactions with related parties
Principal amount										$ 280,500
Interest income recorded													200
Maximum exposure under guaranty	$ 609,300										609,300		609,300
Number of bridge loans originated | loan										12
Number of multifamily properties renovated | property										72
Entity controlled by our chief executive officer
Agreements and transactions with related parties
Reimbursement for flights chartered by the company's executives													100	$ 300
Certain Officers And Managers [Member] | Mezzanine loans | Maturity Date January 2024 [Member]
Agreements and transactions with related parties
Fixed rate of interest (as a percent)									10.00%
Certain Officers And Managers [Member] | Bridge Loan Six Multifamily Properties [Member] | Maturity Date September 2019 [Member]
Agreements and transactions with related parties
Principal amount																		$ 48,000
Number of properties owned | property																		6
Base spread (as a percent)																		4.50%
Interest income recorded													$ 100
Number of bridge loans paid off | loan															4		1
Proceeds from repayment in full									$ 10,900						$ 28,300		$ 6,800
Certain Officers And Managers [Member] | Bridge Loan Six Multifamily Properties [Member] | Maturity Date September 2019 [Member] | Minimum
Agreements and transactions with related parties
Percentage of ownership interest of related party in the entity																		10.50%
Base spread (as a percent)																		0.25%
Certain Officers And Managers [Member] | Bridge Loan Six Multifamily Properties [Member] | Maturity Date September 2019 [Member] | Maximum
Agreements and transactions with related parties
Percentage of ownership interest of related party in the entity																		12.00%
Ginkgo Investment Company LLC [Member] | Fannie Mae
Agreements and transactions with related parties
Loan purchased a multifamily apartment complex which assumed																	$ 8,300
Percentage of maximum loss-sharing obligation unpaid principal balance																	20.00%
Percentage of loan assumption fee																	1.00%
Percentage of ownership after transaction													3.60%
Ginkgo Investment Company LLC [Member] | Maximum | Fannie Mae
Agreements and transactions with related parties
Servicing revenue													$ 100
Consortium Of Affiliated Investors [Member] | Lexford Portfolio
Agreements and transactions with related parties
Management fee, percentage of gross revenues of underlying properties													4.75%
Real estate investment fund sponsored and managed by Chief executive officer and imediate family member of chief executive officer | Bridge loans | Maturity date of March 2024
Agreements and transactions with related parties
Principal amount		$ 63,400
Interest income recorded											$ 700		$ 700
Real estate investment fund sponsored and managed by Chief executive officer and imediate family member of chief executive officer | Bridge loans | Maturity date of March 2024 | LIBOR
Agreements and transactions with related parties
Base spread (as a percent)		3.75%
LIBOR floor (as a percentage)		0.25%

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- Definition

Numbers of operating partnership units issued or issuable in consideration for the business combination.

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Amount of cash distribution received from related party.

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The amount of mortgage loans converted to mezzanine loans during the reporting period.

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The amount represents the entity owned annual fee.

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- Definition

Represents information pertaining to the percentage of indirect ownership in a business.

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No definition available.

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- Definition

Represents the percentage of noncontrolling interest in the equity method investment acquired by the entity.

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No definition available.

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- Definition

Minimum variable interest rate for loans receivable.

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- Definition

Represents the fixed interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans.

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The number of multifamily properties renovated.

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The number of portfolios of multifamily properties as of the balance sheet date.

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Represents number of preferred stock shares paired with each operating partnership unit.

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- Definition

Represents the maximum percentage of ownership interest of the Company's common stock allowed under the company's charter.

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No definition available.

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- Definition

Represents the cash outflow during the reporting period in respect of payments for loans and investments funded and purchased by the reporting entity.

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No definition available.

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The percentage of equity participation interest.

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Represent information pertaining to percentage of loan assumption fee.

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No definition available.

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Represents information pertaining to percentage of maximum loss-sharing obligation unpaid principal balance.

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Represents the percentage of outstanding membership interest of a related party in another related party.

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The minimum amount the entity agreed to fund under the related party commitment.

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Represents the percentage of ownership of common stock or equity participation owned by related party.

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Represent information pertaining to related party, percentage of management.

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Represents the number of bridge loan originated with relevant mortgage property owned by related parties.

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Represents the number of bridge loans paid off to the related party.

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Represents the percentage of voting power held by a related party.

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- Definition

The amount of reimbursements made to related party during the period for flights chartered by the company's executives.

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No definition available.

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Represents the number of common shares held by a related party.

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Amount of decrease in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate, from collection of principal.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
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-Section 12
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-Subsection 29

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-Name Accounting Standards Codification
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Amount of contractual principal due at origination of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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-Name Regulation S-X (SX)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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-SubTopic 310
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Amount for accounts payable to related parties.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
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