| Form N-CSR Cover | 6 Months Ended |
| May 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Federated Hermes International Series, Inc. |
| Entity Central Index Key | 0000742286 |
| Document Period End Date | May 31, 2024 |
| Shareholder Report | 6 Months Ended |
| May 31, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Federated Hermes International Series, Inc. |
| Entity Central Index Key | 0000742286 |
| Document Period End Date | May 31, 2024 |
| C000024762 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Global Total Return Bond Fund |
| Class Name | Class A Shares |
| Trading Symbol | FTIIX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Federated Hermes Global Total Return Bond Fund (the “Fund”) for the period of December 1, 2023 to May 31, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at FederatedHermes.com/us/FundInformation |
| Additional Information Phone Number | 1‑800‑341‑7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A Shares $ 1.02 % |
| Expenses Paid, Amount | $ 51 |
| Expense Ratio, Percent | 1.02% |
| Net Assets | $ 16,619,184 |
| Holdings Count | Holding | 192 |
| Investment Company Portfolio Turnover | 20% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $ % Number of Investments $ % Portfolio Turnover Rate $ % |
| Holdings [Text Block] | Fund Holdings Top Countries 1 Top Currencies 1 1 Reflects the pro rata portfolio composition of underlying affiliated investment companies (other than an affiliated money market mutual fund) in which the Fund invested greater than 10% of its net assets as of the date specified above. Accordingly, the percentages of total net assets shown in the table will differ from those presented on the Portfolio of Investments. |
| C000024764 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Global Total Return Bond Fund |
| Class Name | Class C Shares |
| Trading Symbol | FTIBX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Federated Hermes Global Total Return Bond Fund (the “Fund”) for the period of December 1, 2023 to May 31, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at FederatedHermes.com/us/FundInformation |
| Additional Information Phone Number | 1‑800‑341‑7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C Shares $ 1.77 % |
| Expenses Paid, Amount | $ 88 |
| Expense Ratio, Percent | 1.77% |
| Net Assets | $ 16,619,184 |
| Holdings Count | Holding | 192 |
| Investment Company Portfolio Turnover | 20% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $ % Number of Investments $ % Portfolio Turnover Rate $ % |
| Holdings [Text Block] | Fund Holdings Top Countries 1 Top Currencies 1 1 Reflects the pro rata portfolio composition of underlying affiliated investment companies (other than an affiliated money market mutual fund) in which the Fund invested greater than 10% of its net assets as of the date specified above. Accordingly, the percentages of total net assets shown in the table will differ from those presented on the Portfolio of Investments. |
| C000176365 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Global Total Return Bond Fund |
| Class Name | Institutional Shares |
| Trading Symbol | FGTBX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Federated Hermes Global Total Return Bond Fund (the “Fund”) for the period of December 1, 2023 to May 31, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at FederatedHermes.com/us/FundInformation |
| Additional Information Phone Number | 1‑800‑341‑7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Shares $ 0.77 % |
| Expenses Paid, Amount | $ 39 |
| Expense Ratio, Percent | 0.77% |
| Net Assets | $ 16,619,184 |
| Holdings Count | Holding | 192 |
| Investment Company Portfolio Turnover | 20% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $ % Number of Investments $ % Portfolio Turnover Rate $ % |
| Holdings [Text Block] | Fund Holdings Top Countries 1 Top Currencies 1 1 Reflects the pro rata portfolio composition of underlying affiliated investment companies (other than an affiliated money market mutual fund) in which the Fund invested greater than 10% of its net assets as of the date specified above. Accordingly, the percentages of total net assets shown in the table will differ from those presented on the Portfolio of Investments. |
| Shareholder Report, Holdings (Details) | May 31, 2024 | |
| C000024762 [Member] | United States Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 37.50% | [1] |
| C000024762 [Member] | Euro Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 22% | [1] |
| C000024762 [Member] | Japan Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.90% | [1] |
| C000024762 [Member] | China Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.10% | [1] |
| C000024762 [Member] | United Kingdom Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.80% | [1] |
| C000024762 [Member] | Canada Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.40% | [1] |
| C000024762 [Member] | South Korea Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.30% | [1] |
| C000024762 [Member] | Australia Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.10% | [1] |
| C000024762 [Member] | Egypt Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [1] |
| C000024762 [Member] | New Zealand Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [1] |
| C000024762 [Member] | CANADA | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.20% | [1] |
| C000024762 [Member] | GERMANY | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.10% | [1] |
| C000024762 [Member] | SPAIN | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.20% | [1] |
| C000024762 [Member] | FRANCE | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 5% | [1] |
| C000024762 [Member] | UNITED KINGDOM | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.60% | [1] |
| C000024762 [Member] | ITALY | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4% | [1] |
| C000024762 [Member] | JAPAN | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.70% | [1] |
| C000024762 [Member] | MEXICO | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.10% | [1] |
| C000024762 [Member] | NEW ZEALAND | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.70% | [1] |
| C000024762 [Member] | UNITED STATES | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 39.40% | [1] |
| C000024764 [Member] | United States Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 37.50% | [2] |
| C000024764 [Member] | Euro Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 22% | [2] |
| C000024764 [Member] | Japan Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.90% | [2] |
| C000024764 [Member] | China Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.10% | [2] |
| C000024764 [Member] | United Kingdom Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.80% | [2] |
| C000024764 [Member] | Canada Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.40% | [2] |
| C000024764 [Member] | South Korea Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.30% | [2] |
| C000024764 [Member] | Australia Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.10% | [2] |
| C000024764 [Member] | Egypt Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [2] |
| C000024764 [Member] | New Zealand Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [2] |
| C000024764 [Member] | CANADA | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.20% | [2] |
| C000024764 [Member] | GERMANY | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.10% | [2] |
| C000024764 [Member] | SPAIN | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.20% | [2] |
| C000024764 [Member] | FRANCE | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 5% | [2] |
| C000024764 [Member] | UNITED KINGDOM | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.60% | [2] |
| C000024764 [Member] | ITALY | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4% | [2] |
| C000024764 [Member] | JAPAN | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.70% | [2] |
| C000024764 [Member] | MEXICO | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.10% | [2] |
| C000024764 [Member] | NEW ZEALAND | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.70% | [2] |
| C000024764 [Member] | UNITED STATES | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 39.40% | [2] |
| C000176365 [Member] | United States Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 37.50% | [3] |
| C000176365 [Member] | Euro Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 22% | [3] |
| C000176365 [Member] | Japan Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.90% | [3] |
| C000176365 [Member] | China Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.10% | [3] |
| C000176365 [Member] | United Kingdom Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.80% | [3] |
| C000176365 [Member] | Canada Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.40% | [3] |
| C000176365 [Member] | South Korea Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.30% | [3] |
| C000176365 [Member] | Australia Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.10% | [3] |
| C000176365 [Member] | Egypt Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [3] |
| C000176365 [Member] | New Zealand Currency [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [3] |
| C000176365 [Member] | CANADA | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.20% | [3] |
| C000176365 [Member] | GERMANY | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.10% | [3] |
| C000176365 [Member] | SPAIN | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.20% | [3] |
| C000176365 [Member] | FRANCE | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 5% | [3] |
| C000176365 [Member] | UNITED KINGDOM | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.60% | [3] |
| C000176365 [Member] | ITALY | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4% | [3] |
| C000176365 [Member] | JAPAN | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.70% | [3] |
| C000176365 [Member] | MEXICO | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.10% | [3] |
| C000176365 [Member] | NEW ZEALAND | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.70% | [3] |
| C000176365 [Member] | UNITED STATES | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 39.40% | [3] |
| [1]Reflects the pro rata portfolio composition of underlying affiliated investment companies (other than an affiliated money market mutual fund) in which the Fund invested greater than 10% of its net assets as of the date specified above. Accordingly, the percentages of total net assets shown in the table will differ from those presented on the Portfolio of Investments.[2]Reflects the pro rata portfolio composition of underlying affiliated investment companies (other than an affiliated money market mutual fund) in which the Fund invested greater than 10% of its net assets as of the date specified above. Accordingly, the percentages of total net assets shown in the table will differ from those presented on the Portfolio of Investments.[3]Reflects the pro rata portfolio composition of underlying affiliated investment companies (other than an affiliated money market mutual fund) in which the Fund invested greater than 10% of its net assets as of the date specified above. Accordingly, the percentages of total net assets shown in the table will differ from those presented on the Portfolio of Investments. | ||
