Line of Credit Facility, Accordion Feature, Increase Limit

No definition available.

Name:	nsa_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	nsa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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.

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+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	instant

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Namespace Prefix:
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Balance Type:
Period Type:

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Period Type:

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

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DEBT FINANCING - Narrative (Details) - Credit Facility - USD ($) $ in Millions	Mar. 31, 2024	Jan. 03, 2023	Jan. 02, 2023
Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,825.0	$ 1,955.0	$ 405.0
Borrowing capacity expansion	2,370.0
Revolving line of credit \| Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	950.0
Revolving line of credit remaining borrowing capacity	805.6
Term loan B \| Unsecured debt
Debt Instrument [Line Items]
Maximum borrowing capacity	145.0
Term loan C \| Unsecured debt
Debt Instrument [Line Items]
Maximum borrowing capacity	325.0
Term loan D \| Unsecured debt
Debt Instrument [Line Items]
Maximum borrowing capacity	275.0
Term loan E \| Unsecured debt
Debt Instrument [Line Items]
Maximum borrowing capacity	130.0
Letter of credit \| Revolving line of credit
Debt Instrument [Line Items]
Letters of credit outstanding	$ 6.4