Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net income attributable to FB Financial Corporation and noncontrolling interest	$ 116,051	$ 120,240	$ 124,571
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets and software	11,966	11,180	8,017
Amortization of core deposit and other intangibles	2,947	3,659	4,585
Amortization of issuance costs on subordinated debt	386	387	387
Capitalization of mortgage servicing rights	(4,984)	(7,192)	(20,809)
Net change in fair value of mortgage servicing rights	7,195	11,308	(32,044)
Stock-based compensation expense	9,485	10,381	9,857
Provision for credit losses on loans HFI	14,667	16,738	10,393
(Reversal of) provision for credit losses on unfunded commitments	(2,663)	(14,199)	8,589
Provision for (reversal of) mortgage loan repurchases	235	(650)	(2,989)
(Accretion) amortization of discounts and premiums on acquired loans, net	(657)	(694)	1,020
Amortization of premiums and discounts on securities, net	2,180	6,106	6,589
Loss from investment securities, net	56,378	13,973	376
Originations of loans held for sale	(1,222,606)	(1,199,362)	(2,403,476)
Repurchases of loans held for sale	0	0	(194)
Proceeds from sale of loans held for sale	1,206,725	1,276,596	3,067,204
Gain on sale and change in fair value of loans held for sale	(33,700)	(28,541)	(47,783)
Net loss on write-downs of premises and equipment, other real estate owned and other assets	2,167	27	265
(Reversal of) provision for deferred income taxes	(1,763)	(1,415)	12,552
Earnings on bank-owned life insurance	(3,753)	(1,871)	(1,452)
Changes in:
Operating lease assets and liabilities, net	(1,287)	3,637	5,030
Other assets and interest receivable	(27,679)	6,564	(7,222)
Accrued expenses and other liabilities	7,510	(15,800)	56,247
Net cash provided by operating activities	138,800	211,072	799,713
Activity in available-for-sale securities:
Sales	526,441	100,463	1,218
Maturities, prepayments and calls	299,814	128,206	204,748
Purchases	(905,431)	(202,054)	(242,889)
Proceeds from sales of equity securities	0	3,091	0
Net change in loans	(211,941)	(97,302)	(1,675,976)
Net sales of FHLB stock	1,441	24,451
Net purchases of FHLB stock			(26,424)
Purchases of premises and equipment	(6,546)	(20,229)	(10,629)
Proceeds from the sale of premises and equipment	1,009	123	875
Proceeds from the sale of other real estate owned	2,323	6,083	4,959
Purchase of equity method securities	(10,000)	0	0
Purchase of equity securities without a readily determinable market value	0	0	(10,000)
Proceeds from the sale of other assets	1,494	1,717	0
Proceeds from bank-owned life insurance	7,392	236	0
Net cash used in investing activities	(294,004)	(55,215)	(1,754,118)
Cash flows from financing activities:
Net increase (decrease) in deposits	657,650	(312,897)	28,784
Net (decrease) increase in securities sold under agreements to repurchase and federal funds purchased	(95,265)	21,819	46,229
Repayment of Bank Term Funding Program borrowings	(130,000)	0	0
Net decrease in short-term FHLB advances	0	(45,000)
Net increase in short-term FHLB advances			175,000
Stock-based compensation withholding payments	(1,846)	(3,379)	(2,842)
Net proceeds from sale of common stock under employee stock purchase program	882	723	1,212
Repurchase of common stock	(12,699)	(4,944)	(39,979)
Dividends paid on common stock	(31,780)	(28,057)	(24,503)
Dividend equivalent payments made upon vesting of equity compensation	(166)	(226)	(168)
Noncontrolling interest distribution	(16)	(16)	(16)
Net cash provided by (used in) financing activities	386,760	(371,977)	183,717
Net change in cash and cash equivalents	231,556	(216,120)	(770,688)
Cash and cash equivalents at beginning of the period	810,932	1,027,052	1,797,740
Cash and cash equivalents at end of the period	1,042,488	810,932	1,027,052
Supplemental cash flow information:
Interest paid	303,662	261,032	63,701
Taxes paid, net	43,195	37,937	906
Supplemental noncash disclosures:
Transfers from loans to other real estate owned	3,458	2,736	1,437
Transfers from loans to other assets	4,362	2,925	0
Transfers from other real estate owned to other assets	0	75	0
Transfers from other real estate owned to premises and equipment	0	0	351
Transfers from loans to loans held for sale	1,054	13,720	46,364
Transfers from loans held for sale to loans	1,850	3,273	24,479
Loans provided for sales of other assets	1,078	911	0
Increase (decrease) in rebooked GNMA loans under optional repurchase program	10,128	(4,982)	26,211
Dividends declared not paid on restricted stock units and performance stock units	374	287	222
Right-of-use assets obtained in exchange for operating lease liabilities	$ 5,973	$ 7,300	$ 25,399