Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	RSUs	PSUs	Total common shareholders' equity	Total common shareholders' equity RSUs	Total common shareholders' equity PSUs	Common stock	Common stock RSUs	Common stock PSUs	Additional paid-in capital	Additional paid-in capital RSUs	Additional paid-in capital PSUs	Retained earnings	Accumulated other comprehensive income (loss), net	Noncontrolling interest
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		8
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
Beginning balance at Dec. 31, 2022	1,325,518			1,325,425			46,738			861,588			586,532	(169,433)	93
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to FB Financial Corporation and noncontrolling interest	71,688			71,680									71,680		8
Other comprehensive income (loss), net of taxes	6,026			6,026										6,026
Repurchase of common stock	(4,944)			(4,944)			(136)			(4,808)
Stock based compensation expense	5,533			5,533			6			5,527
Restricted stock units vested and distributed, net of shares withheld	(1,606)	(1,315)		(1,606)	(1,315)		115	68		(1,721)	(1,383)
Shares issued under employee stock purchase program			$ 321			$ 321			$ 8			$ 313
Dividends declared	(14,169)			(14,169)									(14,169)
Noncontrolling interest distribution	(8)														(8)
Ending balance at Jun. 30, 2023	1,387,044			1,386,951			46,799			859,516			644,043	(163,407)	93
Beginning balance at Mar. 31, 2023	1,369,789			1,369,696			46,763			856,628			615,871	(149,566)	93
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to FB Financial Corporation and noncontrolling interest	35,307			35,299									35,299		8
Other comprehensive income (loss), net of taxes	(13,841)			(13,841)										(13,841)
Stock based compensation expense	3,248			3,248			5			3,243
Restricted stock units vested and distributed, net of shares withheld	(154)	$ (170)		(154)	$ (170)		23	$ 8		(177)	$ (178)
Dividends declared	(7,127)			(7,127)									(7,127)
Noncontrolling interest distribution	(8)														(8)
Ending balance at Jun. 30, 2023	$ 1,387,044			$ 1,386,951			$ 46,799			$ 859,516			$ 644,043	$ (163,407)	$ 93