Debt Instrument, Decrease in Periodic Payment

No definition available.

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Balance Type:	credit
Period Type:	duration

- Definition

Impairment of Real Estate, Percentage

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Lessee, Operating Lease, Liability, to be Paid Monthly

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Number of Real Estate Properties, Sold

+ References

No definition available.

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Balance Type:	na
Period Type:	duration

- Definition

Number of Real Estate Properties with Leases Extension

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Assets Acquired

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Number of Impaired Real Estate Properties, Vacant

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Number of Operating Leases with Tenant Improvements

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Number of Real Estate Properties, Held-for-Sale

+ References

No definition available.

+ Details

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Namespace Prefix:	cik0001645873_
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Balance Type:	na
Period Type:	duration

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Balance Type:	credit
Period Type:	duration

- Definition

For transactions that are recognized separately from the acquisition of assets and assumptions of liabilities in the business combination, such as related to pre-existing relationships with the acquiree, this element represents the disclosure of the amount of acquisition related costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

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-Name Accounting Standards Codification
-Topic 210
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Balance Type:	debit
Period Type:	duration

- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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Period Type:	instant

- Definition

Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=120154696&loc=d3e54445-107959

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Term of lessor's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
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Balance Type:	na
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cash outflow for costs that are essential to originate the lease and would not otherwise have been incurred without the lease agreement. Amount includes, but is not limited to, cash outflows to evaluate the lessee's credit condition, guarantees, and collateral and cash outflows for costs incurred in negotiating, processing, and executing the lease agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cash received for the sale of real estate that is not part of an investing activity during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Period Type:	duration

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REAL ESTATE INVESTMENTS - Narrative (FY) (Details)											3 Months Ended						4 Months Ended	6 Months Ended			12 Months Ended
REAL ESTATE INVESTMENTS - Narrative (FY) (Details)	Dec. 31, 2020 USD ($) property state	Dec. 16, 2020 USD ($)	Oct. 29, 2020 USD ($)	Oct. 28, 2020 USD ($)	Sep. 16, 2020 USD ($)	Aug. 27, 2020 USD ($)	Aug. 03, 2020 USD ($)	Aug. 01, 2020 USD ($)	Apr. 01, 2020 USD ($)	Dec. 31, 2019 USD ($) property	Jun. 30, 2021 USD ($) property state	Mar. 31, 2021 USD ($) lease	Dec. 31, 2020 USD ($) property state	Sep. 30, 2020 property	Jun. 30, 2020 USD ($) property	Mar. 31, 2020 USD ($) property	Apr. 30, 2020 USD ($) lease	Jun. 30, 2021 USD ($) property state	Dec. 31, 2020 USD ($) property lease state	Jun. 30, 2020 USD ($) property	Dec. 31, 2020 USD ($) property state	Dec. 31, 2019 USD ($) property
Real Estate [Line Items]
Number of real estate properties \| property	36										38		36					38	36		36
Number of states in which entity operates \| state	14										14		14					14	14		14
Number of real estate properties acquired \| property	0										0		0		0			0	0	0	0
Number of impaired real estate properties, vacant \| property	2												2			2			2		2
Impairment of real estate investment properties											$ (400,999)		$ 761,100		$ 349,457	$ 9,157,068		$ (400,999)		$ 9,506,525	$ 10,267,625	$ 0
Impairment charge percentage	2.50%												2.50%		0.10%	2.20%			2.50%	0.10%	2.50%
Capitalized acquisition fees paid to Former Advisor										$ 5,459												5,459
Disposal group, including discontinued operation, consideration	$ 31,096,403												$ 31,096,403						$ 31,096,403		$ 31,096,403
Proceeds from sale of real estate investments																						0
Lease termination fee			$ (1,350,000)																		$ (1,039,648)	0
Weighted average amortization period																		9 years 4 months 24 days			9 years 4 months 24 days
Number of properties classified as real estate held for sale \| property	4														4						(9)
Number of real estate properties sold																			5		5
REIT I
Real Estate [Line Items]
Revenue of acquiree																						0
24 Hour Fitness \| Mortgage Notes Payable
Real Estate [Line Items]
Monthly mortgage payment									$ 32,000
Decrease in monthly mortgage payment									$ 8,000
Taylor Fresh Foods
Real Estate [Line Items]
Capitalized acquisition fees paid to Former Advisor										$ 741,000												741,000
Revenue of acquiree																						$ 548,362
Dana
Real Estate [Line Items]
Lease termination fee								$ (1,381,767)
Rent payments per month								$ 65,000
Tenant-in-common \| Real Estate Investment
Real Estate [Line Items]
Ownership (as a percent)	72.70%										72.70%		72.70%					72.70%	72.70%		72.70%
REIT I
Real Estate [Line Items]
Number of real estate properties acquired \| property	14									20	14		14					14	14		14	20
Retail
Real Estate [Line Items]
Number of real estate properties \| property	11										12		11					12	11		11
Disposal group, including discontinued operation, consideration												$ 13,714,188
Number of properties classified as real estate held for sale \| property	4									3			3	2	3						(8)
Number of real estate properties sold \| lease												3							4
Retail \| 24 Hour Fitness
Real Estate [Line Items]
Impairment of real estate investment properties															$ 0	$ 5,664,517				$ 5,664,517	$ 5,664,517
Disposal group, including discontinued operation, consideration		$ 9,052,941
Proceeds from sale of real estate investments		$ 1,324,383
Retail \| Rite Aid
Real Estate [Line Items]
Impairment of real estate investment properties															$ 349,457						349,457
Disposal group, including discontinued operation, consideration	$ 7,250,000						$ 7,250,000						$ 7,250,000						$ 7,250,000		7,250,000
Proceeds from sale of real estate investments							$ 3,299,016
Retail \| Walgreens Santa Maria and Stockbridge
Real Estate [Line Items]
Aggregate payment of lease incentives																	$ 990,000
Number of operating leases with lease incentives \| lease																	2
Retail \| Walgreens
Real Estate [Line Items]
Operating leases extension																	10 years
Retail \| Walgreens Stockbridge
Real Estate [Line Items]
Disposal group, including discontinued operation, consideration	5,538,462					$ 5,538,462							5,538,462						5,538,462		5,538,462
Proceeds from sale of real estate investments						$ 5,296,356
Operating leases extension																	10 years
Retail \| Island Pacific Supermarket
Real Estate [Line Items]
Disposal group, including discontinued operation, consideration	$ 3,155,000				$ 3,155,000								$ 3,155,000						$ 3,155,000		$ 3,155,000
Proceeds from sale of real estate investments					$ 1,124,016
Retail \| Chevron Gas Station
Real Estate [Line Items]
Number of properties classified as real estate held for sale \| property	2
Retail \| Dollar General, Castalia and Lakeside
Real Estate [Line Items]
Number of properties with leases extension \| property																2
Retail \| REIT I
Real Estate [Line Items]
Number of real estate properties acquired \| property										5												5
Office
Real Estate [Line Items]
Number of real estate properties \| property	14										14		14					14	14		14
Office \| REIT I
Real Estate [Line Items]
Number of real estate properties acquired \| property										4												4
Industrial
Real Estate [Line Items]
Number of real estate properties \| property	11										12		11					12	11		11
Number of properties classified as real estate held for sale \| property															1						(1)
Number of real estate properties sold \| lease																			1
Industrial \| Dana
Real Estate [Line Items]
Impairment of real estate investment properties															$ 0					2,184,395	$ 2,184,395
Industrial \| Rite Aid
Real Estate [Line Items]
Impairment of real estate investment properties															349,457					349,457
Industrial \| Dinan Cars
Real Estate [Line Items]
Impairment of real estate investment properties															$ 0					$ 1,308,156	1,308,156
Disposal group, including discontinued operation, consideration	$ 6,100,000			$ 6,100,000									$ 6,100,000						$ 6,100,000		$ 6,100,000
Proceeds from sale of real estate investments				$ 3,811,580
Industrial \| REIT I
Real Estate [Line Items]
Number of real estate properties acquired \| property										5												5
Land
Real Estate [Line Items]
Number of real estate properties \| property	1												1						1		1