Name:	fii_DefinedContributionPercentageEmployeeServicePeriodAfterInitialVesting
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

The first employee salary deferral contribution percentage that must be elected to receive the first employer matching contribution percentage.

No definition available.

Name:	fii_DefinedContributionPlanEmployeeSalaryDeferralContributionPercentage1
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The second employee salary deferral contribution percentage that must be elected to receive the second employer matching contribution percentage.

No definition available.

Name:	fii_DefinedContributionPlanEmployeeSalaryDeferralContributionPercentage2
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The number of hours an employee must provide service to the Company each year in order to be eligible to participate in the profit sharing plan.

No definition available.

Name:	fii_DefinedContributionPlanEmployeeServiceHoursForParticipationPerYear
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

The number of hours an employee must provide service to the Company each year in order to be eligible to receive employer matching contributions.

No definition available.

Name:	fii_DefinedContributionPlanEmployeeServiceHoursForVestingPerYear
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

The number of years an employee must provide service to the Company in order to be eligible to receive employer matching contributions.

No definition available.

Name:	fii_DefinedContributionPlanEmployeeServicePeriodForVestingYears
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

The Company's matching contribution percentage on the first employee salary deferral contribution percentage.

No definition available.

Name:	fii_DefinedContributionPlanEmployerMatchingContributionPercentage1
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The Company's matching contribution percentage on the second employee salary deferral contribution percentage.

No definition available.

Name:	fii_DefinedContributionPlanEmployerMatchingContributionPercentage2
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The incremental percentage an employee is vested each year in the employer matching contributions after fulfilling the minimum required years of service.

No definition available.

Name:	fii_DefinedContributionPlanIncrementalPercentageVestedAfterRequiredYearsOfService
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The number of shares of Class B common stock held in the profit sharing plan as of the balance sheet date.

No definition available.

Name:	fii_DefinedContributionPlanNumberOfSharesOfClassBCommonStock
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

The number of shares of Class B common stock eligible to be purchased as part of the employee stock purchase plan.

No definition available.

Name:	fii_DefinedContributionPlanNumberOfSharesOfClassBCommonStockEligibleForPurchaseInEmployeeStockPurchasePlan
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

The total number of shares of Class B common stock purchased under the employee stock purchase plan since inception.

No definition available.

Name:	fii_DefinedContributionPlanNumberOfSharesOfClassBCommonStockPurchasedUnderPlanSinceInception
Namespace Prefix:	fii_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

The percentage an employee is vested in the employer matching contributions after fulfilling the minimum required years of service.

No definition available.

Name:	fii_DefinedContributionPlanPercentageVestedAfterRequiredYearsOfService
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The maximum salary deferral contribution percentage an employee can make to participate in the Plan.

No definition available.

Name:	fii_DefinedContributionPlanSalaryDeferralContributionPercentageMaximum
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The minimum salary deferral contribution percentage an employee can make to participate in the Plan.

No definition available.

Name:	fii_DefinedContributionPlanSalaryDeferralContributionPercentageMinimum
Namespace Prefix:	fii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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