The percentage of estimated total annualized cost of capital.

No definition available.

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Balance Type:	na
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- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	star_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

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

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=star_SterlingNationalBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=star_EastWestBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=star_AppleBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=star_PeapackGladstoneBankMember
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Borrowings, Secured Credit Facility Commitment (Details) - USD ($)	3 Months Ended
	Jun. 30, 2023	Dec. 31, 2022	Sep. 26, 2022	Sep. 16, 2022	Jun. 22, 2022	May 06, 2022	Jan. 12, 2022	Jul. 02, 2021
Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	$ 200,000,000	$ 200,000,000		$ 200,000,000		$ 125,000,000	$ 80,000,000
Borrowing capacity can be increased	350,000,000
Fair value of borrowings outstanding	$ 160,000,000	145,000,000
Estimated total annualized cost of capital percentage	8.00%
Secured Credit Facility [Member] \| Prime Rate [Member]
Credit Facility Commitment [Abstract]
Interest rate	0.35%
Revolving Credit Line [Member]
Credit Facility Commitment [Abstract]
Fair value of borrowings outstanding	$ 0	8,000,000
Sterling National Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment								$ 55,000,000
East West Bank [Member] \| Revolving Credit Line [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment			$ 21,000,000		$ 25,000,000
Webster Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	67,500,000	67,500,000
Blue Ridge Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	25,000,000	25,000,000
First Foundation Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	20,000,000	20,000,000
Mitsubishi HC Capital America, Inc. [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	20,000,000	20,000,000
Woodforest National Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	20,000,000	20,000,000
Forbright Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	17,500,000	17,500,000
Apple Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	15,000,000	15,000,000
Peapack-Gladstone Bank [Member] \| Secured Credit Facility [Member]
Credit Facility Commitment [Abstract]
Secured credit facility commitment	$ 15,000,000	$ 15,000,000