Consolidated statements of comprehensive income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 190,301	$ 63,629	$ 83,814
Other comprehensive (loss) income, net of tax:
Net change in unrealized (loss) gain in available-for-sale securities, net of tax (benefits) expenses of $(7,224), $5,781 and $6,227	(22,475)	18,430	17,693
Reclassification adjustment for (gain) loss on sale of securities included in net income, net of tax expenses (benefits) of $33, $348 and $(24)	(93)	(987)	67
Net change in unrealized loss in hedging activities, net of tax expenses (benefits) of $293, $(363) and $(322)	831	(1,031)	(914)
Reclassification adjustment for gain on hedging activities, net of tax expenses of $0, $337 and $170	0	(955)	(481)
Total other comprehensive (loss) income, net of tax	(21,737)	15,457	16,365
Comprehensive income	168,564	79,086	100,179
Comprehensive income applicable to noncontrolling interest	16	8	0
Comprehensive income applicable to FB Financial Corporation	$ 168,548	$ 79,078	$ 100,179