v3.26.1
Shareholder Report
 6 Months Ended
Apr. 30, 2026
USD ($)
$ / shares
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name Legg Mason Partners Investment Trust
Entity Central Index Key 0000880366
Entity Investment Company Type N-1A
Document Period End Date Apr. 30, 2026
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Class 1  
Shareholder Report [Line Items]  
Fund Name Franklin Global Equity Fund
Class Name Class 1
Trading Symbol LMPEX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Franklin Global Equity Fund for the period November 1, 2025, to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
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 1
$49
0.95%
[1]
Expenses Paid, Amount $ 49
Expense Ratio, Percent 0.95%
Net Assets $ 593,371,091
Holdings Count | $ / shares 129
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of April 30, 2026)
Total Net Assets
$593,371,091
Total Number of Portfolio Holdings
129
Portfolio Turnover Rate
15%
Holdings [Text Block]
WHAT DID THE FUND INVEST IN? (as of April 30, 2026)
Portfolio Composition* (% of Total Investments)
image
 [2]
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class A  
Shareholder Report [Line Items]  
Fund Name Franklin Global Equity Fund
Class Name Class A
Trading Symbol CFIPX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Franklin Global Equity Fund for the period November 1, 2025, to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
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
$61
1.18%
[3]
Expenses Paid, Amount $ 61
Expense Ratio, Percent 1.18%
Net Assets $ 593,371,091
Holdings Count | $ / shares 129
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of April 30, 2026)
Total Net Assets
$593,371,091
Total Number of Portfolio Holdings
129
Portfolio Turnover Rate
15%
Holdings [Text Block]
WHAT DID THE FUND INVEST IN? (as of April 30, 2026)
Portfolio Composition* (% of Total Investments)
image
 [4]
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class C  
Shareholder Report [Line Items]  
Fund Name Franklin Global Equity Fund
Class Name Class C
Trading Symbol SILLX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Franklin Global Equity Fund for the period November 1, 2025, to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
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
$98
1.91%
[5]
Expenses Paid, Amount $ 98
Expense Ratio, Percent 1.91%
Net Assets $ 593,371,091
Holdings Count | $ / shares 129
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of April 30, 2026)
Total Net Assets
$593,371,091
Total Number of Portfolio Holdings
129
Portfolio Turnover Rate
15%
Holdings [Text Block]
WHAT DID THE FUND INVEST IN? (as of April 30, 2026)
Portfolio Composition* (% of Total Investments)
image
 [6]
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class I  
Shareholder Report [Line Items]  
Fund Name Franklin Global Equity Fund
Class Name Class I
Trading Symbol SMYIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Franklin Global Equity Fund for the period November 1, 2025, to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
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 I
$48
0.94%
[7]
Expenses Paid, Amount $ 48
Expense Ratio, Percent 0.94%
Net Assets $ 593,371,091
Holdings Count | $ / shares 129
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of April 30, 2026)
Total Net Assets
$593,371,091
Total Number of Portfolio Holdings
129
Portfolio Turnover Rate
15%
Holdings [Text Block]
WHAT DID THE FUND INVEST IN? (as of April 30, 2026)
Portfolio Composition* (% of Total Investments)
image
 [8]
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
Class IS  
Shareholder Report [Line Items]  
Fund Name Franklin Global Equity Fund
Class Name Class IS
Trading Symbol SMYSX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Franklin Global Equity Fund for the period November 1, 2025, to April 30, 2026.
Additional Information [Text Block] You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents. You can also request this information by contacting us at 877-6LM-FUND/656-3863.
Additional Information Phone Number 877-6LM-FUND/656-3863
Additional Information Website https://www.franklintempleton.com/regulatory-fund-documents
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 IS
$42
0.82%
[9]
Expenses Paid, Amount $ 42
Expense Ratio, Percent 0.82%
Net Assets $ 593,371,091
Holdings Count | $ / shares 129
Investment Company Portfolio Turnover 15.00%
Additional Fund Statistics [Text Block]
KEY FUND STATISTICS (as of April 30, 2026)
Total Net Assets
$593,371,091
Total Number of Portfolio Holdings
129
Portfolio Turnover Rate
15%
Holdings [Text Block]
WHAT DID THE FUND INVEST IN? (as of April 30, 2026)
Portfolio Composition* (% of Total Investments)
image
 [10]
Updated Prospectus Web Address https://www.franklintempleton.com/regulatory-fund-documents
[1]
† Annualized.
[2]
* Does not include derivatives, except purchased options, if any.  
[3]
† Annualized.
[4]
* Does not include derivatives, except purchased options, if any.  
[5]
† Annualized.
[6]
* Does not include derivatives, except purchased options, if any.  
[7]
† Annualized.
[8]
* Does not include derivatives, except purchased options, if any.  
[9]
† Annualized.
[10]
* Does not include derivatives, except purchased options, if any.