Investments - Narrative (Details) $ in Thousands	12 Months Ended
Sep. 30, 2020 USD ($)
GCIC Senior Loan Fund LLC
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Dividend income	$ 1,905

Amount of operating dividend income on securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2)
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

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Balance Type:	credit
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