Percent of outstanding stock.

No definition available.

Name:	sfnc_PercentOfOutstandingStock
Namespace Prefix:	sfnc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of additional shares to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	sfnc_StockRepurchaseProgramNumberOfAdditionalSharesToBeRepurchased
Namespace Prefix:	sfnc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_EquityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

+ Details

Name:	us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

Common Stock - Textual (Details)	Feb. 08, 2018	Jul. 23, 2012 shares	Jun. 30, 2018 shares	Apr. 19, 2018 shares	Apr. 18, 2018 shares	Dec. 31, 2017 shares
Equity [Abstract]
Conversion ratio	2
Common stock, shares authorized (in shares)			175,000,000	175,000,000	120,000,000	120,000,000
Number of shares authorized to be repurchased (in shares)		1,700,000
Percent of outstanding stock (as percent)		2.00%
Number of additional shares to be repurchased (in shares)		308,272