REAL ESTATE INVESTMENTS, NET - Intangible Assets Amortization (Q2) (Details) - USD ($)	6 Months Ended	12 Months Ended
Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019
Real Estate [Line Items]
July through December 2021	$ 938,913
2022	1,877,826
2023	787,228
2024	709,832
Net amount	$ 4,313,799	$ 5,127,788	$ 7,700,000
Below-Market Lease Intangibles
Weighted-average remaining amortization period	9 years 4 months 24 days	9 years 4 months 24 days
Tenant Origination and Absorption Costs
Real Estate [Line Items]
July through December 2021	$ 1,609,387
2022	2,682,533	$ 3,801,383
2023	1,805,532	2,628,700
2024	1,689,428	1,751,653
2025	1,311,545	1,625,159
2026	601,734	1,242,973
Thereafter	2,659,530	3,046,229
Net amount	$ 12,359,689	$ 14,096,097	21,261,362
Below-Market Lease Intangibles
Weighted-average remaining amortization period	7 years 1 month 6 days	7 years 1 month 6 days
Above-Market Lease Intangibles
Real Estate [Line Items]
July through December 2021	$ 64,909
2022	129,823	$ 129,823
2023	127,174	129,823
2024	122,543	127,174
2025	115,996	122,543
2026	78,557	115,995
Thereafter	116,927	195,484
Net amount	$ 755,929	$ 820,842	1,251,734
Below-Market Lease Intangibles
Weighted-average remaining amortization period	6 years 9 months 18 days	7 years 2 months 12 days
Below-Market Lease Intangibles
Below-Market Lease Intangibles
July through December 2021	$ (727,614)
2022	(1,217,029)	$ (1,462,730)
2023	(921,169)	(1,217,076)
2024	(917,750)	(921,169)
2025	(917,750)	(917,750)
2026	(912,347)	(917,750)
Thereafter	(6,216,928)	(7,129,262)
Net amount	$ (11,830,587)	$ (12,565,737)	$ (14,591,359)
Weighted-average remaining amortization period	11 years 10 months 24 days	12 years 2 months 12 days

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized in remainder of current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization income for lease with finite life acquired as part of real property acquisition at below market lease rate expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount after amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

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Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in remainder of current fiscal year.

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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

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