VESSELS UNDER CAPITAL LEASE, NET 4 (Details) (USD $) In Millions, unless otherwise specified	Jul. 31, 2011
Capital leases [Abstract]
Outstanding lease obligation settled in full from termination of lease agreement between Holyrood Shipping Plc and Dresdner Kleinwort Leasing	$ 75.7

Outstanding lease obligation settled in full from termination of lease agreement between Holyrood Shipping Plc and Dresdner Kleinwort Leasing

No definition available.

Name:	fro_OutstandingLeaseObligationSettledInFullFromTerminationOfLeaseAgreementBetweenHolyroodShippingPlcAndDresdnerKleinwortLeasing
Namespace Prefix:	fro_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant