v3.25.1
Label Element Value
Prospectus [Line Items] rr_ProspectusLineItems  
Document Type dei_DocumentType 497
Document Period End Date dei_DocumentPeriodEndDate Dec. 31, 2024
Entity Registrant Name dei_EntityRegistrantName PUTNAM INVESTMENT FUNDS
Entity Central Index Key dei_EntityCentralIndexKey 0000932101
Entity Inv Company Type dei_EntityInvCompanyType N-1A
Amendment Flag dei_AmendmentFlag false
Putnam Research Fund  
Prospectus [Line Items] rr_ProspectusLineItems  
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual fund operating expenses (expenses you pay each year as a percentage of the value of your investment)
Expense Example [Heading] rr_ExpenseExampleHeading Example
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock

The following hypothetical example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. It assumes that you invest $10,000 in the fund for the time periods indicated and then, except as indicated, redeem all your shares at the end of those periods. It assumes a 5% return on your investment each year and that the fund’s operating expenses remain the same. Only the first year of each period in the example takes into account the fee waiver/expense reimbursement arrangements described above. Your actual costs may be higher or lower.

Putnam Research Fund | Class A  
Prospectus [Line Items] rr_ProspectusLineItems  
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.54%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.25%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.22%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.01%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.12%) [1]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.89% [2]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 661
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 867
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 1,090
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,730
Putnam Research Fund | Class C  
Prospectus [Line Items] rr_ProspectusLineItems  
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.54%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 1.00%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.22%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.76%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.12%) [1]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.64% [2]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 267
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 543
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 943
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 1,865
Expense Example, No Redemption, 1 Year rr_ExpenseExampleNoRedemptionYear01 167
Expense Example, No Redemption, 3 Years rr_ExpenseExampleNoRedemptionYear03 543
Expense Example, No Redemption, 5 Years rr_ExpenseExampleNoRedemptionYear05 943
Expense Example, No Redemption, 10 Years rr_ExpenseExampleNoRedemptionYear10 $ 1,865
Putnam Research Fund | Class R  
Prospectus [Line Items] rr_ProspectusLineItems  
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.54%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets 0.50%
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.22%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 1.26%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.12%) [1]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 1.14% [2]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 116
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 387
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 679
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 1,510
Putnam Research Fund | Class R6  
Prospectus [Line Items] rr_ProspectusLineItems  
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.54%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.12%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.66%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.17%) [1]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.49% [2]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 50
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 194
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 351
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 396
Putnam Research Fund | Class Y  
Prospectus [Line Items] rr_ProspectusLineItems  
Management Fees (as a percentage of Assets) rr_ManagementFeesOverAssets 0.54%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses (as a percentage of Assets): rr_OtherExpensesOverAssets 0.22%
Expenses (as a percentage of Assets) rr_ExpensesOverAssets 0.76%
Fee Waiver or Reimbursement rr_FeeWaiverOrReimbursementOverAssets (0.27%) [1]
Net Expenses (as a percentage of Assets) rr_NetExpensesOverAssets 0.49% [2]
Expense Example, with Redemption, 1 Year rr_ExpenseExampleYear01 $ 50
Expense Example, with Redemption, 3 Years rr_ExpenseExampleYear03 216
Expense Example, with Redemption, 5 Years rr_ExpenseExampleYear05 396
Expense Example, with Redemption, 10 Years rr_ExpenseExampleYear10 $ 917
[1] Effective June 2, 2025, the fund's investment manager has agreed to waive fees and/or reimburse operating expenses (excluding 12b-1 fees, interest expense, payments under the fund's investor servicing contract, brokerage commissions, taxes, acquired fund fees and expenses, investment-related expenses (such as short selling and lines of credit costs) and extraordinary expenses) for the fund so that the ratio of total annual fund operating expenses will not exceed 0.49% for each share class. In addition, the fund's investor servicing agent has agreed to waive all investor servicing fees with respect to Class R6 and Y shares of the fund. These contractual fee waiver and expense reimbursement arrangements run until November 30, 2026. During their terms, the fee waiver and expense reimbursement arrangements may not be terminated or amended without approval of the board of trustees.
[2] Total annual fund operating expenses after expense reimbursement have been restated to reflect current waiver arrangements and operating expense caps.