Stock-Based Compensation - Summary of Accumulated Stock Units (Detail) - $ / shares	Jun. 30, 2025	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Accumulated stock units	118,710	120,984
Average price	$ 48.04	$ 44.7

Deferred compensation arrangement with individual accumulated stock units For deferred board fees.

No definition available.

Name:	banf_DeferredCompensationArrangementWithIndividualAccumulatedStockUnitsForDeferredBoardFees
Namespace Prefix:	banf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant