Stock-Based Compensation - Additional Information (Detail) - USD ($)				3 Months Ended
	Mar. 31, 2024	Jun. 01, 2023	May 25, 2023	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Net cash settlement for stock options, cost				$ 0	$ 0
Deferred board fees percentage for stock units accumulation				100.00%
RSU's Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares for future grants	462,925			462,925
Option exercisable rate	20.00%
Option exercisable period	2 years
Options expire period			10 years
Options vest and exercisable Description				The restricted stock units ("RSU's") vest beginning two years from the date of grant at the rate of 20% per year for five years.
Vesting period in years			5 years
Employee Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan termination date		Jun. 01, 2023
Option exercisable rate				25.00%
Options expire period				15 years
Vesting period in years, start				4 years
Options vest and exercisable Description				and are exercisable beginning four years from the date of grant at the rate of 25% per year for four years, and expire no later than the end of fifteen years from the date of grant
Vesting period in years				4 years
Employee Plan [Member] | Employee Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period in years				5 years
Employee Plan [Member] | RSU's Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period in years				6 years
Non-Employee Directors Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan termination date		Jun. 01, 2023
Option exercisable rate				25.00%
Option exercisable period				1 year
Options expire period				15 years
Options vest and exercisable Description				The remaining options will continue to vest and are exercisable beginning one year from the date of grant at the rate of 25% per year for four years
Vesting period in years				4 years
Banc First Deferred Stock Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option plan termination date				Dec. 31, 2024
Number of shares available for future issuance under deferred compensation plan	15,923			15,923
Number of shares of common stock distributed				5,022	17,392