Name:	fbk_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsConversionOfDeferredCompensationPlanInPeriod
Namespace Prefix:	fbk_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Share based compensation arrangement by share based payment award equity instruments other than options conversion of deferred compensation plan in period weighted average grant date fair value.

No definition available.

Name:	fbk_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsConversionOfDeferredCompensationPlanInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	fbk_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Share based compensation arrangement by share based payment award equity instruments other than options conversion of equity based incentive plan in period.

No definition available.

Name:	fbk_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsConversionOfEquityBasedIncentivePlanInPeriod
Namespace Prefix:	fbk_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Share based compensation arrangement by share based payment award equity instruments other than options conversion of equity based incentive plan in period weighted average grant date fair value.

No definition available.

Name:	fbk_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsConversionOfEquityBasedIncentivePlanInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	fbk_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Share based compensation arrangement by share based payment award equity instruments other than options vested and nonvested number.

No definition available.

Name:	fbk_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndNonvestedNumber
Namespace Prefix:	fbk_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Share based compensation arrangement by share based payment award equity instruments other than options vested and nonvested weighted average grant date fair value.

No definition available.

Name:	fbk_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix:	fbk_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.