XML 79 R66.htm IDEA: XBRL DOCUMENT v2.4.0.8

Stockholders' equity and employee benefit plans (Employee Benefit Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stockholders' Equity and Employee Benefit Plans Disclosure [Abstract]
Employee contribution benefit plan expense	$ 8.2	$ 5.8	$ 4.3
Allowable purchase interval duration	6 months
Price per share to fair market value	85.00%

X

- Definition

Employee Stock Ownership Plan (ESOP), Allowable Purchase Interval Duration

+ References

No definition available.

+ Details

Name:	fet_EmployeeStockOwnershipPlanESOPAllowablePurchaseIntervalDuration
Namespace Prefix:	fet_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Employee Stock Ownership Plan, Price Per Share to Fair Market Value

+ References

No definition available.

+ Details

Name:	fet_EmployeeStockOwnershipPlanPricePerSharetoFairMarketValue
Namespace Prefix:	fet_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	fet_StockholdersEquityAndEmployeeBenefitPlansDisclosureAbstract
Namespace Prefix:	fet_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of the cost recognized during the period for defined contribution plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 70

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942

+ Details

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration