National Storage Affiliates Trust Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

RELATED PARTY TRANSACTIONS (Details)

RELATED PARTY TRANSACTIONS (Details) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
RELATED PARTY TRANSACTIONS (Details) $ in Thousands	Sep. 30, 2021 USD ($) property	Jun. 30, 2021 USD ($) property	Mar. 31, 2021 USD ($) property	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) property shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 property tranche
Related Party Transaction [Line Items]
Payroll and related costs reimbursed to the PROs by the Company	$ 39,465			$ 31,546	$ 110,723	$ 92,395
Number of properties acquired \| property	76	20	23		119
Consideration in acquisition transaction	$ 599,277	$ 269,393	$ 165,963		$ 1,034,633
Value of OP Equity	31,074	$ 24,102	$ 22,897		78,073
Supervisory and Administrative Fee Agreement \| Management \| Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Supervisory and administrative fees paid to the PROs	5,400			3,700	14,500	12,500
Payroll Services \| Management \| Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Payroll and related costs reimbursed to the PROs by the Company	6,900			$ 5,700	19,900	20,000
Due Diligence Costs \| Management \| Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Due diligence expenses payable to the PROs	$ 300				$ 800	$ 200
Self storage property purchase from affiliate of trustee \| Affiliated entity
Related Party Transaction [Line Items]
Number of properties acquired \| property					2		1
Number of earnout tranches \| tranche							3
Consideration in acquisition transaction					$ 20,600
Self storage property purchase from affiliate of trustee \| Affiliated entity \| Six month tranche
Related Party Transaction [Line Items]
Earnout performance periods							6 months
Self storage property purchase from affiliate of trustee \| Affiliated entity \| 12 month and 18 month tranches
Related Party Transaction [Line Items]
Consideration in acquisition transaction					$ 3,900
Self storage property purchase from affiliate of trustee \| Affiliated entity \| 12 month tranche
Related Party Transaction [Line Items]
Earnout performance periods							12 months
Self storage property purchase from affiliate of trustee \| Affiliated entity \| 18 month tranche
Related Party Transaction [Line Items]
Earnout performance periods							18 months
Self storage property purchase from affiliate of trustee \| Affiliated entity \| Mr. J. Timothy Warren \| OP units
Related Party Transaction [Line Items]
Number of OP Units in acquisition (in shares) \| shares					38,413
Value of OP Equity					$ 1,600
Self storage property purchase from affiliate of trustee \| Affiliated entity \| Mr. J. Timothy Warren \| OP units \| 12 month and 18 month tranches
Related Party Transaction [Line Items]
Number of OP Units in acquisition (in shares) \| shares					22,794
Value of OP Equity					$ 1,100
Minimum \| Supervisory and Administrative Fee Agreement \| Management \| Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Supervisory and administrative fee agreement of gross revenue, percent					5.00%
Maximum \| Supervisory and Administrative Fee Agreement \| Management \| Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Supervisory and administrative fee agreement of gross revenue, percent					6.00%