XML 42 R33.htm IDEA: XBRL DOCUMENT
v3.23.1

Portfolio Company Investments - Schedule of Investments Type With Corresponding Percentage of Total Portfolio Investments (Parenthetical) (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 | Dec. 31, 2022
Summary of Investment Holdings [Line Items] |  |
Percentage of Fair Value | 100.00% | 100.00%
Percentage of Cost | 100.00% | 100.00%
Unitranche Investments [Member] |  |
Summary of Investment Holdings [Line Items] |  |
Percentage of Fair Value | 41.40% | 42.10%
Percentage of Cost | 42.70% | 43.40%

X
- Definition Percentage of cost. + References No definition available. + Details
Name: | fdus_Percentageofcost
Namespace Prefix: | fdus_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of fair value. + References No definition available. + Details
Name: | fdus_Percentageoffairvalue
Namespace Prefix: | fdus_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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. + References No definition available. + Details
Name: | us-gaap_SummaryOfInvestmentHoldingsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=fdus_UnitrancheInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |