Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Total common shareholders' equity	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss), net	Noncontrolling interest
Beginning balance at Dec. 31, 2020	$ 1,291,382	$ 1,291,289	$ 47,222	$ 898,847	$ 317,625	$ 27,595	$ 93
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to FB Financial Corporation and noncontrolling interest	96,176	96,168			96,168
Other comprehensive income (loss), net of taxes	(9,190)	(9,190)				(9,190)
Stock based compensation expense	5,181	5,181	5	5,176
Restricted stock units vested and distributed, net of shares withheld	(1,940)	(1,940)	112	(2,052)
Shares issued under employee stock purchase program	833	833	22	811
Dividends declared	(10,620)	(10,620)			(10,620)
Noncontrolling interest distribution	(8)						(8)
Ending balance at Jun. 30, 2021	1,371,814	1,371,721	47,361	902,782	403,173	18,405	93
Beginning balance at Mar. 31, 2021	1,329,196	1,329,103	47,332	900,521	365,192	16,058	93
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to FB Financial Corporation and noncontrolling interest	43,302	43,294			43,294		8
Other comprehensive income (loss), net of taxes	2,347	2,347				2,347
Stock based compensation expense	2,515	2,515	2	2,513
Restricted stock units vested and distributed, net of shares withheld	(225)	(225)	27	(252)
Dividends declared	(5,313)	(5,313)			(5,313)
Noncontrolling interest distribution	(8)						(8)
Ending balance at Jun. 30, 2021	1,371,814	1,371,721	47,361	902,782	403,173	18,405	93
Beginning balance at Dec. 31, 2021	1,432,695	1,432,602	47,549	892,529	486,666	5,858	93
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to FB Financial Corporation and noncontrolling interest	54,589	54,581			54,581		8
Other comprehensive income (loss), net of taxes	(126,353)	(126,353)				(126,353)
Repurchase of common stock	(32,743)	(32,743)	(795)	(31,948)
Stock based compensation expense	5,620	5,620	2	5,618
Restricted stock units vested and distributed, net of shares withheld	(2,146)	(2,146)	111	(2,257)
Shares issued under employee stock purchase program	687	687	15	672
Dividends declared	(12,396)	(12,396)			(12,396)
Noncontrolling interest distribution	(8)						(8)
Ending balance at Jun. 30, 2022	1,319,945	1,319,852	46,882	864,614	528,851	(120,495)	93
Beginning balance at Mar. 31, 2022	1,379,869	1,379,776	47,488	888,168	515,664	(71,544)	93
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to FB Financial Corporation and noncontrolling interest	19,353	19,345			19,345
Other comprehensive income (loss), net of taxes	(48,951)	(48,951)				(48,951)
Repurchase of common stock	(26,540)	(26,540)	(650)	(25,890)
Stock based compensation expense	3,038	3,038	1	3,037
Restricted stock units vested and distributed, net of shares withheld	(658)	(658)	43	(701)
Dividends declared	(6,158)	(6,158)			(6,158)
Noncontrolling interest distribution	(8)						(8)
Ending balance at Jun. 30, 2022	$ 1,319,945	$ 1,319,852	$ 46,882	$ 864,614	$ 528,851	$ (120,495)	$ 93