Represents the number of foreign countries in which the entity has exploratory and development interests.

No definition available.

Name:	fst_ExploratoryAndDevelopmentInterestsInForeignCountriesNumber
Namespace Prefix:	fst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

ORGANIZATION AND BASIS OF PRESENTATION (Details)	Sep. 30, 2012 foreign_country	Sep. 30, 2011	Jun. 01, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Exploratory and development interests in foreign countries (in foreign countries)	2
Percentage of subsidiary common stock sold in initial public offering (as a percent)			18.00%
Percentage of subsidiary stock distributed in spin-off (as a percent)		82.00%