Preparation of Interim Financial Statements (Details)	Sep. 30, 2025 center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of financial centers	223

Represents the entity's number of financial centers as of the balance sheet date.

No definition available.

Name:	sfnc_NumberOfFinancialCenters
Namespace Prefix:	sfnc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant