Note 14 - Income Taxes (Details Textual) - CAD ($)	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Statement Line Items [Line Items]
Tax penalties and interest	$ 149,245	$ 193,262	$ (0)

The amount of tax penalty and interest incurred during the period.

No definition available.

Name:	fmst_TaxPenaltiesAndInterest
Namespace Prefix:	fmst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration