Debt Securities, Allowance for Credit Loss

No definition available.

Name:	sfnc_DebtSecuritiesAllowanceforCreditLoss
Namespace Prefix:	sfnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Amount of allowance for credit loss at acquisition date of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
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-URI http://asc.fasb.org/extlink&oid=118955579&loc=SL82922903-210455

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

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+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Name:	us-gaap_OffBalanceSheetCreditLossLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References

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+ Details

Name:	us-gaap_RetainedEarningsAccumulatedDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	sfnc_CumulativeEffectPeriodOfAdoptionAxis=sfnc_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Preparation of Interim Financial Statements (Details) $ in Thousands	Jan. 01, 2020 USD ($)	Mar. 31, 2020 USD ($) financial_center	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Number of financial centers \| financial_center		240
Allowance for credit loss		$ 243,195
Unfunded commitments, allowance for credit loss		29,400	$ 8,400
Cumulative effect on retained earnings		$ 778,893	$ 848,848
Impact of adoption of 2016-13 \| Accounting Standards Update 2016-13
Lessee, Lease, Description [Line Items]
Allowance for credit loss	$ 151,400
Unfunded commitments, allowance for credit loss	24,000
Debt securities, allowance for credit loss	742
Cumulative effect on retained earnings	128,100
Purchased with credit deterioration, allowance for credit loss	$ 5,400