Quarterly report [Sections 13 or 15(d)]

Long-Term Debt - Additional Information (Detail)

v3.26.3
Long-Term Debt - Additional Information (Detail)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Aug. 12, 2026
USD ($)
Feb. 16, 2026
USD ($)
Feb. 16, 2024
USD ($)
Days
Feb. 02, 2023
USD ($)
Jun. 24, 2022
USD ($)
Feb. 02, 2021
USD ($)
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Oct. 13, 2026
USD ($)
Debt Instrument [Line Items]                        
Debt instrument, issuance costs, net             $ 22,000   $ 22,000   $ 21,900  
Debt instrument, unamortized discount costs             3,300   $ 3,300   6,500  
Debt instrument, maturity date                 Jun. 24, 2027      
Interest expense                 $ 12,810 $ 12,428    
Accretion expense             1,139 $ 1,237 3,376 3,638    
Long term debt, fair value             204,610   204,610   186,489  
Revolving Credit Line                        
Debt Instrument [Line Items]                        
Debt Instrument Issued Principal $ 2,500                      
Amounts drawn under long term debt             $ 0   $ 0      
Unpaid interest are due and payable date Jun. 27, 2027                      
Outstanding borrowings bear simple interest 12.00%                      
Revolving line of credit in an aggregate principal amount $ 2,500                      
Other Equity Method Investees [Member]                        
Debt Instrument [Line Items]                        
Company's acquisition equity interests             5.00%   5.00%      
June Secured Debentures [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, face value         $ 99,700              
Debt instrument, maturity date         Jun. 24, 2027              
Interest expense             $ 2,800 2,600 $ 8,200 7,600    
Accretion expense             800 800 2,400 2,300    
Long term debt, fair value         $ 84,500   169,921   169,921   154,569  
June Secured Debentures [Member] | Minimum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, interest rate stated percentage         8.00%              
June Secured Debentures [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument interest percentage on event of default         11.00%              
June Unsecured Debentures [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, face value         $ 20,000              
Debt instrument, maturity date         Jun. 24, 2027              
Interest expense             600 500 1,600 1,500    
Accretion expense             300 300 800 800    
Long term debt, fair value         $ 14,900              
June Unsecured Debentures [Member] | Minimum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, interest rate stated percentage         8.00%              
June Unsecured Debentures [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument interest percentage on event of default         11.00%              
Additional Secured Debentures [Member]                        
Debt Instrument [Line Items]                        
Interest expense             700 700 2,100 1,900    
Long term debt, fair value         $ 25,000              
Additional Secured Debentures [Member] | Secured Debenture Purchase Agreement [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, face value         $ 25,000              
Debt instrument, maturity date         Jun. 24, 2027              
Additional Secured Debentures [Member] | Secured Debenture Purchase Agreement [Member] | Minimum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, interest rate stated percentage         8.00%              
Additional Secured Debentures [Member] | Secured Debenture Purchase Agreement [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument interest percentage on event of default         11.00%              
Long-Term Debt [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, interest paid             700 1,200 $ 700 1,200    
Subsequent Event [Member] | Revolving Credit Line                        
Debt Instrument [Line Items]                        
Amounts drawn under long term debt                       $ 1,600
iAnthus New Jersey LLC [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, description about qualified financing                 “Qualified Financing” means a transaction or series of related transactions resulting in net proceeds to the ICH of not less than $10 million from the subscription of the ICH's securities, including, but not limited to, a private placement or rights offering.      
Lenders [Member] | June Secured Debentures [Member] | Minimum [Member] | Other Equity Method Investees [Member]                        
Debt Instrument [Line Items]                        
Company's acquisition equity interests         5.00%              
Lenders [Member] | June Unsecured Debentures [Member] | Minimum [Member] | Other Equity Method Investees [Member]                        
Debt Instrument [Line Items]                        
Company's acquisition equity interests         5.00%              
Lenders [Member] | Additional Secured Debentures [Member] | Minimum [Member] | Other Equity Method Investees [Member]                        
Debt Instrument [Line Items]                        
Company's acquisition equity interests         5.00%              
2024 NJ Amendment [Member] | iAnthus New Jersey LLC [Member]                        
Debt Instrument [Line Items]                        
Debt Instrument Redemption Price Percentage Of Principal Amount Redeemed   2.00%                    
Investment Owned Balance Principal Amount   $ 8,400                    
Amount Of Impairment To Carrying Amount Of Regulatory Assets             200   $ 200      
Secured Debt [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, interest rate stated percentage         8.00%              
New Jersey Senior Secured Bridge Notes [Member]                        
Debt Instrument [Line Items]                        
Percentage of outstanding shares held                 5.00%      
New Jersey Senior Secured Bridge Notes [Member] | iAnthus New Jersey LLC [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, face value       $ 1,400   $ 11,000            
Debt instrument, maturity date       Feb. 02, 2024   Feb. 02, 2023            
Debt instrument, interest rate on secured notes           14.00%            
Debt instrument, threshold limit of qualified financing, net proceeds not less than the subscription of securities                 $ 10,000      
Debt instrument, interest rate stated percentage       12.00%                
Debt instrument, percentage of total outstanding debt instrument principal amount       10.00%                
Interest expense             200 300 700 1,100    
Accretion expense             $ 100 $ 200 200 $ 600    
Long term debt, fair value     $ 8,200                  
New Jersey Senior Secured Bridge Notes [Member] | Prospective Default [Member] | iAnthus New Jersey LLC [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, interest rate on secured notes           8.00%            
New Jersey Senior Secured Bridge Notes [Member] | 2024 NJ Amendment [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, maturity date, range end   Jun. 24, 2027                    
Debt Instrument Issued Principal   $ 11,000                    
Revolving line of credit in an aggregate principal amount   $ 11,000                    
New Jersey Senior Secured Bridge Notes [Member] | 2024 NJ Amendment [Member] | Minimum [Member]                        
Debt Instrument [Line Items]                        
Debt Instrument Issuance Date 1   Feb. 02, 2021                    
New Jersey Senior Secured Bridge Notes [Member] | 2024 NJ Amendment [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, maturity date   Feb. 16, 2026                    
New Jersey Senior Secured Bridge Notes [Member] | 2024 NJ Amendment [Member] | iAnthus New Jersey LLC [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, face value     $ 1,600                  
Non-Operational Cash Receipts                 $ 400   $ 7,400  
Debt instrument, interest rate stated percentage     12.00%                  
Debt instrument, percentage of total outstanding debt instrument principal amount     10.00%                  
Debt instrument, first quarterly payment date     May 16, 2024                  
Debt instrument, convertible, threshold trading days | Days     20                  
Debt instrument, non-operational cash receipts, utilization rate     25.00%                  
Debt instrument, payment towards outstanding principal amount     $ 5,000                  
New Jersey Senior Secured Bridge Notes [Member] | 2024 NJ Amendment [Member] | iAnthus New Jersey LLC [Member] | Minimum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, maturity date, range start     Feb. 16, 2024                  
New Jersey Senior Secured Bridge Notes [Member] | 2024 NJ Amendment [Member] | iAnthus New Jersey LLC [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument, maturity date, range start     Feb. 16, 2026