N-2 - $ / shares	9 Months Ended
N-2 - $ / shares	Jun. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021
Cover [Abstract]
Entity Central Index Key	0001504619
Amendment Flag	false
Securities Act File Number	814-00891
Document Type	10-Q
Entity Registrant Name	PENNANTPARK FLOATING RATE CAPITAL LTD.
Entity Address, Address Line One	1691 Michigan Avenue
Entity Address, City or Town	Miami Beach
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	33139
City Area Code	786
Local Phone Number	297-9500
Entity Emerging Growth Company	false
General Description of Registrant [Abstract]
Risk Factors [Table Text Block]	Item 1A. Risk Factors In addition to the other information set forth in this Report, you should consider carefully the factors discussed below, as well as in Part I “Item 1A. Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended September 30, 2022 filed on November 17, 2022, which could materially affect our business, financial condition and/or operating results. The risks described below, as well as in our Annual Report on Form 10-K are not the only risks facing PennantPark Floating Rate Capital Ltd. Additional risks and uncertainties not currently known to us or that we currently deem to be immaterial also may materially and adversely affect our business, financial condition and/or operating results. We and our portfolio companies may maintain cash balances at financial institutions that exceed federally insured limits and may otherwise be materially affected by adverse developments affecting the financial services industry, such as actual events or concerns involving liquidity, defaults or non-performance by financial institutions or transactional counterparties. Our cash is held in accounts at U.S. banking institutions that we believe are of high quality. Cash held by us and by our portfolio companies in non-interest-bearing and interest-bearing operating accounts may exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance limits. If such banking institutions were to fail, we or our portfolio companies could lose all or a portion of those amounts held in excess of such insurance limitations. In addition, actual events involving limited liquidity, defaults, non-performance or other adverse developments that affect financial institutions, transactional counterparties or other companies in the financial services industry or the financial services industry generally, or concerns or rumors about any events of these kinds or other similar risks, have in the past and may in the future lead to market-wide liquidity problems, which could adversely affect our and our portfolio companies’ business, financial condition, results of operations, or prospects. Although we assess our and our portfolio companies’ banking relationships as we believe necessary or appropriate, our and our portfolio companies’ access to funding sources and other credit arrangements in amounts adequate to finance or capitalize our respective current and projected future business operations could be significantly impaired by factors that affect us or our portfolio companies, the financial institutions with which we or our portfolio companies have arrangements directly, or the financial services industry or economy in general. These factors could include, among others, events such as liquidity constraints or failures, the ability to perform obligations under various types of financial, credit or liquidity agreements or arrangements, disruptions or instability in the financial services industry or financial markets, or concerns or negative expectations about the prospects for companies in the financial services industry. These factors could involve financial institutions or financial services industry companies with which we or our portfolio companies have financial or business relationships, but could also include factors involving financial markets or the financial services industry generally. In addition, investor concerns regarding the U.S. or international financial systems could result in less favorable commercial financing terms, including higher interest rates or costs and tighter financial and operating covenants, or systemic limitations on access to credit and liquidity sources, thereby making it more difficult for us or our portfolio companies to acquire financing on acceptable terms or at all.
NAV Per Share	$ 10.96	$ 11.62	$ 12.21	$ 12.62
Cash Balances at Financial Institutions that Exceed Federally Insured Limits
General Description of Registrant [Abstract]
Risk [Text Block]	We and our portfolio companies may maintain cash balances at financial institutions that exceed federally insured limits and may otherwise be materially affected by adverse developments affecting the financial services industry, such as actual events or concerns involving liquidity, defaults or non-performance by financial institutions or transactional counterparties. Our cash is held in accounts at U.S. banking institutions that we believe are of high quality. Cash held by us and by our portfolio companies in non-interest-bearing and interest-bearing operating accounts may exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance limits. If such banking institutions were to fail, we or our portfolio companies could lose all or a portion of those amounts held in excess of such insurance limitations. In addition, actual events involving limited liquidity, defaults, non-performance or other adverse developments that affect financial institutions, transactional counterparties or other companies in the financial services industry or the financial services industry generally, or concerns or rumors about any events of these kinds or other similar risks, have in the past and may in the future lead to market-wide liquidity problems, which could adversely affect our and our portfolio companies’ business, financial condition, results of operations, or prospects. Although we assess our and our portfolio companies’ banking relationships as we believe necessary or appropriate, our and our portfolio companies’ access to funding sources and other credit arrangements in amounts adequate to finance or capitalize our respective current and projected future business operations could be significantly impaired by factors that affect us or our portfolio companies, the financial institutions with which we or our portfolio companies have arrangements directly, or the financial services industry or economy in general. These factors could include, among others, events such as liquidity constraints or failures, the ability to perform obligations under various types of financial, credit or liquidity agreements or arrangements, disruptions or instability in the financial services industry or financial markets, or concerns or negative expectations about the prospects for companies in the financial services industry. These factors could involve financial institutions or financial services industry companies with which we or our portfolio companies have financial or business relationships, but could also include factors involving financial markets or the financial services industry generally. In addition, investor concerns regarding the U.S. or international financial systems could result in less favorable commercial financing terms, including higher interest rates or costs and tighter financial and operating covenants, or systemic limitations on access to credit and liquidity sources, thereby making it more difficult for us or our portfolio companies to acquire financing on acceptable terms or at all.