RELATED PARTY TRANSACTIONS - Leasing transactions (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Related Party Transaction [Line Items]
Present value of obligations under finance leases	$ 52,444		$ 56,277
SFL
Related Party Transaction [Line Items]
Charter hire payable (principal and interest)	3,942	$ 4,360
Lease interest expense	2,002	2,455
Contingent rental (income) expense	(1,624)	8,270
Present value of obligations under finance leases	$ 52,444	$ 59,974

The increases or decreases in lease payments that result from changes occurring after the inception of the lease in the factors (other than the passage of time) on which lease payments are based, except that any escalation of minimum lease payments relating to increases in construction or acquisition cost of the leased property or for increases in some measure of cost or value during the construction or preconstruction period, are excluded from contingent rentals. Contingent rentals also may include amounts for which the triggering events have not yet occurred or the specified targets for which have not yet been achieved (such as sales based percentage rent), but which events are considered probable of occurring or which specified targets are considered probable of being achieved.

No definition available.

Name:	fro_ContingentRentalExpenseIncome
Namespace Prefix:	fro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration