Accounts receivable, net - Accrued Defective Return and Discount Accounts Roll Forward (Details) - USD ($)	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Accounts Receivable, Accrued Defective Return and Discount, Current [Roll Forward]
Beginning balance	$ 1,007,319	$ 1,001,927
Provision	348,130	123,538
Ending balance	$ 1,355,449	$ 1,125,465

The amount as of the balance sheet date of accrued defective return and discount on accounts receivables, classified as current.

No definition available.

Name:	fgi_AccountsReceivableAccruedDefectiveReturnAndDiscountCurrent
Namespace Prefix:	fgi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant