Represents a decrease to intangible assets due to the sale of a business during the period.

No definition available.

Name:	sfnc_DecreaseInIntangibleAssetsFromTheSaleOfBusiness
Namespace Prefix:	sfnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

Name:	us-gaap_AmortizationOfIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

No definition available.

+ Details

Name:	us-gaap_FinitelivedIntangibleAssetsAcquired1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

+ Details

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

+ Details

Name:	us-gaap_GoodwillAcquiredDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sfnc_CoreDepositPremiumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=sfnc_SalinaBankingOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sfnc_BooksOfBusinessIntangibleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=sfnc_PurchasedCreditCardRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=sfnc_CitizensNationalBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=sfnc_LibertyBancsharesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=sfnc_CommunityFirstBancsharesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=sfnc_OzarkTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 6 - Goodwill and Other Intangible Assets (Details Textual) - USD ($)	3 Months Ended				12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 09, 2016	Feb. 27, 2015
Goodwill		$ 327,686,000			$ 348,505,000	$ 327,686,000
Amortization of Intangible Assets					5,945,000	4,889,000	$ 1,979,000
Core Deposit Premium [Member]
Amortization of Intangible Assets					$ 4,400,000	3,900,000	1,400,000
Core Deposit Premium [Member] \| Salina Banking Operations [Member]
Decrease in Intangible Assets from The Sale of Business			$ 382,000
Core Deposit Premium [Member] \| Minimum [Member]
Finite-Lived Intangible Asset, Useful Life					10 years
Core Deposit Premium [Member] \| Maximum [Member]
Finite-Lived Intangible Asset, Useful Life					15 years
Books of Business Intangible [Member]
Amortization of Intangible Assets					$ 1,100,000	528,000	151,000
Books of Business Intangible [Member] \| Minimum [Member]
Finite-Lived Intangible Asset, Useful Life					10 years
Books of Business Intangible [Member] \| Maximum [Member]
Finite-Lived Intangible Asset, Useful Life					15 years
Purchased Credit Card Relationships [Member]
Amortization of Intangible Assets					$ 414,000	414,000	$ 414,000
Citizens National Bank [Member]
Goodwill								$ 21,495,000
Goodwill, Acquired During Period					21,500,000
Citizens National Bank [Member] \| Core Deposit Premium [Member]
Finite-lived Intangible Assets Acquired					$ 5,100,000
Citizens National Bank [Member] \| Books of Business Intangible [Member]
Finite-lived Intangible Assets Acquired	$ 591,000
Liberty Bancshares, Inc. [Member]
Goodwill									$ 95,207,000
Goodwill, Acquired During Period						95,200,000
Liberty Bancshares, Inc. [Member] \| Core Deposit Premium [Member]
Finite-lived Intangible Assets Acquired						14,600,000
Community First Bancshares Inc [Member]
Goodwill									$ 110,440,000
Goodwill, Acquired During Period						110,400,000
Community First Bancshares Inc [Member] \| Core Deposit Premium [Member]
Finite-lived Intangible Assets Acquired						11,300,000
Community First Bancshares Inc [Member] \| Books of Business Intangible [Member]
Finite-lived Intangible Assets Acquired				$ 420,000
Ozark Trust [Member]
Goodwill, Acquired During Period						$ 13,300,000
Ozark Trust [Member] \| Books of Business Intangible [Member]
Finite-lived Intangible Assets Acquired		$ 9,700,000