Consolidated Statements of Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 19,353	$ 43,302	$ 54,589	$ 96,176
Other comprehensive (loss) income, net of tax:
Net change in unrealized (loss) gain in available-for-sale securities, net of tax (benefits) expense of $(17,343), $798, $(44,826) and $(2,654)	(49,233)	2,286	(127,408)	(9,562)
Reclassification adjustment for gain on sale of securities included in net income, net of tax expenses of $0, $2, $1 and $4	(1)	(6)	(2)	(11)
Amount of gain recognized in other comprehensive income, net of tax expense of $99, $23, $372 and $135	283	67	1,057	383
Total other comprehensive (loss) income, net of tax	(48,951)	2,347	(126,353)	(9,190)
Comprehensive (loss) income applicable to FB Financial Corporation and noncontrolling interest	(29,598)	45,649	(71,764)	86,986
Comprehensive income applicable to noncontrolling interest	8	8	8	8
Comprehensive (loss) income applicable to FB Financial Corporation	$ (29,606)	$ 45,641	$ (71,772)	$ 86,978