Related Party Transactions - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Transaction [Line Items]
Deposits from related parties	$ 316,141	$ 347,660
Other income	6,095	5,213	$ 19,047
Master loan purchase agreement, maximum amount	250
Amortized cost	$ 1,658,779	1,705,574
Manufactured loan housing securities
Related Party Transaction [Line Items]
Loan purchase agreement, term	5 years
Loans purchased	$ 33,164	0
Amortized cost	32,154
Purchase agreements		0
Preferred Stock
Related Party Transaction [Line Items]
Equity security without readily determinable market value	10,000	10,000
Directors
Related Party Transaction [Line Items]
Operating lease expense	385	396	497
Directors \| FBK Aviation, LLC \| Aviation Time Sharing Agreements
Related Party Transaction [Line Items]
Other income	28	52	$ 21
Unfunded Loan Commitment \| Certain Executive Officers, Certain Management and Directors and Their Associates
Related Party Transaction [Line Items]
Unfunded commitments	$ 44,206	$ 31,564

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Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI) and investment in equity security without readily determinable fair value.

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Amount of operating lease expense. Excludes sublease income.

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Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

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The cash outflow for the purchase of loan receivable arising from the financing of goods and services.

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Amount of deposits held by the entity for a related party (entity, shareholder, employee).

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Amount, after the effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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