v3.21.2

Stockholders' Equity - Narrative - Preferred Stock (Details)	6 Months Ended
	Jun. 30, 2021 class_of_stock shares	Dec. 31, 2020 shares
Equity [Abstract]
Preferred stock, number of classes or series the Board of Directors is authorized to classify or reclassify \| class_of_stock	1
Preferred stock, number of classes or series the Board of Directors is authorized to issue \| class_of_stock	1
Preferred stock, shares issued (in shares) \| shares	0	0
Preferred stock, shares outstanding (in shares) \| shares	0	0

Represents the minimum number of classes or series of preferred stock the Board of Directors is authorized to classify or reclassify, in one or more series, any unissued shares and designate the preferences, rights and privileges of such shares of preferred stock.

+ References

No definition available.

+ Details

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Namespace Prefix:	sfar_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of classes or series of preferred stock the Board of Directors is authorized to issue under charter.

+ References

No definition available.

+ Details

Name:	sfar_PreferredStockNumberofClassesorSeriesAuthorizedforIssuancePerCharterMinimum
Namespace Prefix:	sfar_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_EquityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Steadfast Apartment REIT, Inc. 10-Q