iAnthus Capital Holdings, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Share Capital - Additional Information (Detail)

Share Capital - Additional Information (Detail) - USD ($) $ in Thousands														3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2023	Jul. 06, 2023	Jun. 27, 2023	May 17, 2023	Apr. 20, 2023	Mar. 03, 2023	Jan. 03, 2023	Dec. 23, 2022	Dec. 08, 2022	Nov. 23, 2022	Sep. 19, 2022	Aug. 18, 2022	Jun. 24, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jun. 23, 2022	Dec. 31, 2021
Fair value adjustment of warrants														$ 0	$ 0	$ 0	$ 100
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation														26		257
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount														4,500		$ 4,500
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition																2 years 8 months 8 days
Stock Issued During Period, Shares, New Issues		19,439			9,255	27,930	15,628
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation		481			3,103		7,776
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation		$ 100			$ 100		$ 200
Share based payment arrangement plan modification fair value of award														$ 0		$ 0
Share-based compensation arrangement by share-based payment award, award vesting period	3 years		3 years							3 years	1 year
Share-based compensation arrangement by share-based payment award, number of shares authorized																			26,881	363,921
Share-based compensation arrangement by share-based payment award, shares issued in period	207,194		12,950	25,977						7,317	27,108
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period				5,587							7,843					97,932,000		263,155,000
Share-based compensation arrangement by share-based payment award, equity instruments other than options, expected to vest in period				20,391							19,265
Warrant Liability [Member]
Derivative liabilities																		$ 0
Julius Kalcevich [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based compensation arrangement by share-based payment award, shares issued in period									27,930
Key Employees [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based compensation arrangement by share-based payment award, award vesting period								3 years
Share-based compensation arrangement by share-based payment award, shares issued in period								21,400
Common Stock [Member]
Stock Issued Under Recapitalization Transaction Shares																	6,072,580,000
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation														(4,818,000)		(15,697,000)
Common Stock [Member] \| MPX [Member]
Stock Issued During Period, Shares, Acquisitions												408
Common Stock [Member] \| Secured Lenders and Unsecured Lenders [Member]
Stock Issued Under Recapitalization Transaction Shares													6,072,580
Maximum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based compensation arrangement by share-based payment award, award vesting period				3 years
Minimum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based compensation arrangement by share-based payment award, award vesting period				1 year
Stock Options Member
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount														$ 0		$ 0
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition																3 years
Share based payment arrangement plan modification fair value of award														0		$ 0
Share-based compensation arrangement by share-based payment award, award vesting period																3 years
Selling, general and administrative expenses
Share-based payment arrangement expense														100	200	$ 100	$ 2,000
Selling, general and administrative expenses \| Restricted Stock Units (RSUs) [Member]
Share-based payment arrangement expense														$ 500	$ 4,400	$ 3,500	$ 25,500