Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 19,175	$ 31,831	$ 90,863	$ 86,420
Other comprehensive (loss) income, net of tax:
Net unrealized loss in available-for-sale securities, net of tax benefit of $(13,819), $(23,750), $(11,650) and $(68,576)	(39,316)	(67,353)	(33,110)	(194,761)
Reclassification adjustment for loss (gain) on sale of securities included in net income, net of tax benefit (expense) of $3,674, $—, $3,674, and $(1)	10,426	(1)	10,426	(3)
Net unrealized (loss) gain in hedging activities, net of tax (benefit) expense of $(35), $145, $(99) and $517	(101)	409	(281)	1,466
Total other comprehensive loss, net of tax	(28,991)	(66,945)	(22,965)	(193,298)
Comprehensive (loss) income applicable to FB Financial Corporation and noncontrolling interest	(9,816)	(35,114)	67,898	(106,878)
Comprehensive income applicable to noncontrolling interest	0	0	8	8
Comprehensive (loss) income applicable to FB Financial Corporation	$ (9,816)	$ (35,114)	$ 67,890	$ (106,886)