Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	Mar. 31, 2026	Sep. 30, 2025
Commitments And Contingencies Disclosure [Line Items]
Commitments to fund investments	$ 581.0	$ 603.7
Maximum
Commitments And Contingencies Disclosure [Line Items]
Unfunded commitments	26.3	$ 65.6
PSSL Subsidiary II \| Maximum
Commitments And Contingencies Disclosure [Line Items]
Unfunded commitments	$ 56.3

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 107
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-107

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6A
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-6A

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