Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income attributable to FB Financial Corporation and noncontrolling interest	$ 120,240	$ 124,571	$ 190,301
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of fixed assets and software	11,180	8,017	8,416
Amortization of core deposit and other intangibles	3,659	4,585	5,473
Amortization of Debt Issuance Costs and Accretion of Premiums	387	387	17
Capitalization of mortgage servicing rights	(7,192)	(20,809)	(39,018)
Net change in fair value of mortgage servicing rights	11,308	(32,044)	3,503
Stock-based compensation expense	10,381	9,857	10,282
Provision for (reversal of) credit losses on loans HFI	16,738	10,393	(38,995)
(Reversal of) provision for credit losses on unfunded commitments	(14,199)	8,589	(1,998)
Provision for mortgage loan repurchases	(650)	(2,989)	(766)
(Accretion) amortization of discounts and premiums on acquired loans, net	(694)	1,020	853
Amortization (accretion) of premiums and discounts on securities, net	6,106	6,589	8,777
Loss (gain) from investment securities, net	13,973	376	(324)
Originations of loans held for sale	(1,199,362)	(2,403,476)	(6,300,892)
Repurchases of loans held for sale	0	(194)	(487)
Proceeds from sale of loans held for sale	1,276,596	3,067,204	6,387,110
Gain on sale and change in fair value of loans held for sale	(28,541)	(47,783)	(161,964)
Net loss (gain) on write-downs of other real estate owned and other assets	27	265	(2,827)
Provision for deferred income taxes	(1,415)	12,552	30,770
Earnings on bank-owned life insurance	(1,871)	(1,452)	(1,542)
Changes in:
Operating lease assets and liabilities, net	3,637	5,030	(969)
Other assets and interest receivable	6,564	(17,222)	59,283
Accrued expenses and other liabilities	(15,800)	56,247	(100,108)
Net cash provided by operating activities	211,072	789,713	54,895
Activity in available-for-sale securities:
Sales	100,463	1,218	8,855
Maturities, prepayments and calls	128,206	204,748	296,256
Purchases	(202,054)	(242,889)	(847,212)
Proceeds from sales of equity securities	3,091	0	0
Net change in loans	(97,302)	(1,675,976)	(309,766)
Sales of FHLB stock	32,444	0	4,294
Purchases of FHLB stock	(7,993)	(26,424)	(5,279)
Purchases of premises and equipment	(20,229)	(10,629)	(6,102)
Proceeds from the sale of premises and equipment	123	875	0
Proceeds from the sale of other real estate owned	6,083	4,959	9,396
Proceeds from the sale of other assets	1,717	0	0
Proceeds from bank-owned life insurance	236	0	0
Net cash used in investing activities	(55,215)	(1,744,118)	(849,558)
Cash flows from financing activities:
Net (decrease) increase in deposits	(312,897)	28,784	1,378,860
Net increase in securities sold under agreements to repurchase and federal funds purchased	21,819	46,229	8,517
Net decrease in short-term FHLB advances and Bank Term Funding Program	(45,000)
Net increase in short-term FHLB advances and Bank Term Funding Program		175,000	0
Payments on subordinated debt	0	0	(60,000)
Payments on other borrowings	0	0	(15,000)
Share based compensation withholding payments	(3,379)	(2,842)	(10,158)
Net proceeds from sale of common stock under employee stock purchase program	723	1,212	1,480
Repurchase of common stock	(4,944)	(39,979)	(7,595)
Dividends paid on common stock	(28,057)	(24,503)	(20,866)
Dividend equivalent payments made upon vesting of equity compensation	(226)	(168)	(717)
Noncontrolling interest distribution	(16)	(16)	(16)
Net cash (used in) provided by financing activities	(371,977)	183,717	1,274,505
Net change in cash and cash equivalents	(216,120)	(770,688)	479,842
Cash and cash equivalents at beginning of the period	1,027,052	1,797,740	1,317,898
Cash and cash equivalents at end of the period	810,932	1,027,052	1,797,740
Supplemental cash flow information:
Interest paid	261,032	63,701	41,238
Taxes paid, net	37,937	906	61,693
Supplemental noncash disclosures:
Transfers from loans to other real estate owned	2,736	1,437	5,262
Transfers from loans to other assets	2,925	0	0
Transfers from other real estate owned to other assets	75	0	0
Transfers from other real estate owned to premises and equipment	0	351	0
Loans provided for sales of other real estate owned	0	0	704
Loans provided for sales of other assets	911	0	0
Transfers from loans to loans held for sale	13,720	46,364	10,408
Transfers from loans held for sale to loans	3,273	24,479	86,315
(Decrease) increase in rebooked GNMA loans under optional repurchase program	(4,982)	26,211	0
Dividends declared not paid on restricted stock units	287	222	400
Right-of-use assets obtained in exchange for operating lease liabilities	$ 7,300	$ 25,399	$ 970