Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net income attributable to FB Financial Corporation and noncontrolling interest	$ 78,157	$ 90,863
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets and software	8,957	7,361
Amortization of core deposit and other intangibles	2,260	2,819
Amortization of issuance costs on subordinated debt	290	290
Capitalization of mortgage servicing rights	(4,067)	(6,134)
Net change in fair value of mortgage servicing rights	11,219	1,789
Stock-based compensation expense	7,261	8,317
Provision for credit losses on loans HFI	7,648	13,603
Provision for (reversal of) credit losses on unfunded commitments	(2,728)	(11,369)
Provision for (reversal of) mortgage loan repurchases	200	(650)
Accretion of discounts and premiums on acquired loans, net	(538)	(617)
Amortization of premiums and discounts on securities, net	2,787	3,959
Loss from investment securities, net	56,378	14,156
Originations of loans held for sale	(913,315)	(970,131)
Proceeds from sale of loans held for sale	911,650	1,013,584
Gain on sale and change in fair value of loans held for sale	(26,008)	(25,847)
Net loss (gain) on write-downs of other real estate owned and other assets	5	(465)
(Reversal of) provision for deferred income taxes	(3,895)	1,660
Earnings on bank-owned life insurance	(3,296)	(1,382)
Changes in:
Operating lease assets and liabilities, net	(1,110)	1,591
Other assets and interest receivable	(22,170)	(14,596)
Accrued expenses and other liabilities	4,985	7,911
Net cash provided by operating activities	114,670	136,712
Activity in available-for-sale securities:
Sales	526,076	75,857
Maturities, prepayments and calls	224,070	91,361
Purchases	(823,976)	(82,829)
Net change in loans	(73,631)	21,419
Proceeds from sales of FHLB stock, net	1,331	23,832
Purchases of premises and equipment	(4,977)	(16,563)
Proceeds from the sale of premises and equipment	489	105
Proceeds from the sale of other real estate owned	1,846	5,692
Proceeds from the sale of other assets	898	1,197
Proceeds from bank-owned life insurance	7,272	236
Net cash (used in) provided by investing activities	(140,602)	120,307
Cash flows from financing activities:
Net increase (decrease) in deposits	423,427	(219,798)
Net decrease in securities sold under agreements to repurchase and federal funds purchased	(89,056)	(12,240)
Repayment of Bank Term Funding Program	(130,000)	0
Net decrease in short-term FHLB advances	0	(175,000)
Share based compensation withholding payments	(1,787)	(3,243)
Net proceeds from sale of common stock under employee stock purchase program	882	723
Repurchase of common stock	(12,699)	(4,944)
Dividends paid on common stock	(23,847)	(21,026)
Dividend equivalent payments made upon vesting of equity compensation	(162)	(217)
Noncontrolling interest distribution	(8)	(8)
Net cash provided by (used in) financing activities	166,750	(435,753)
Net change in cash and cash equivalents	140,818	(178,734)
Cash and cash equivalents at beginning of the period	810,932	1,027,052
Cash and cash equivalents at end of the period	951,750	848,318
Supplemental cash flow information:
Interest paid	229,275	185,513
Taxes paid, net	34,173	37,875
Supplemental noncash disclosures:
Transfers from loans to other real estate owned	2,400	657
Transfers from loans to other assets	3,316	2,233
Transfers from other real estate owned to other assets	0	75
Transfers from loans to loans held for sale	167	11,351
Transfers from loans held for sale to loans	1,850	3,076
Loans provided for sales of other assets	924	516
Increase (decrease) in rebooked GNMA loans under optional repurchase program	9,308	(4,137)
Trade date payable - securities	0	10,930
Trade date receivable - securities	365	789
Dividends declared not paid on restricted stock units and performance stock units	279	241
Right-of-use assets obtained in exchange for operating lease liabilities	$ 3,925	$ 5,617