Debt - (Details 1) - Falcon Credit Facility [Member]	12 Months Ended
Dec. 31, 2020
Maximum [Member]
Ratio of total net debt to EBITDAX, as defined in the Credit Facility	4.00%
Minimum [Member]
Ratio of current assets to current liabilities, as defined in the Credit Facility	1.00%

Financial covenant ratio of current assets to current liabilities.

No definition available.

Name:	flmn_FinancialCovenantRatioOfCurrentAssetsToCurrentLiabilities
Namespace Prefix:	flmn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration