Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating Loss Carryforwards [Line Items]
Net operating loss	$ 805	$ 1,088
Franklin Financial Network, Inc.
Operating Loss Carryforwards [Line Items]
Net operating loss	$ 3,835	$ 5,179

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-8

Name:	us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant