Note 8 - Income Taxes (Details) - Tax Effects of Temporary Differences Related to Deferred Taxes Included in Other Liabilities: (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Loans acquired	$ 16,925sfnc_DeferredTaxAssetsLoansAcquired	$ 14,456sfnc_DeferredTaxAssetsLoansAcquired
FDIC true-up liability	2,792sfnc_DeferredTaxAssetsFdicTrueUpLiab	2,918sfnc_DeferredTaxAssetsFdicTrueUpLiab
Allowance for loan losses	11,749	11,307
Valuation of foreclosed assets	14,167sfnc_DeberredTaxAssetsonForclosedAssets	14,053sfnc_DeberredTaxAssetsonForclosedAssets
Tax NOLs from acquisition	11,819	11,819
Deferred compensation payable	1,536	1,263
Vacation compensation	1,456	1,148
Accumulated depreciation	1,937	4,939
Loan interest	1,693sfnc_DeferredTaxAssetsLoanInterest	767sfnc_DeferredTaxAssetsLoanInterest
Accrued pension and profit sharing	1,793	1,682
Accrued equity and other compensation	3,356	579
Acquired securities	2,568	2,643
Accrued merger related costs	2,464	1,032
Unrealized loss on available-for-sale securities	862	1,938
Other	2,283us-gaap_DeferredTaxAssetsOther	15us-gaap_DeferredTaxAssetsOther
Gross deferred tax assets	77,400us-gaap_DeferredTaxAssetsGross	70,559us-gaap_DeferredTaxAssetsGross
Deferred tax liabilities:
Goodwill and other intangible amortization	(16,953)	(6,803)
FDIC acquired assets	(4,377)	(14,524)
Deferred loan fee income and expenses, net	(1,515)	(2,697)
FHLB stock dividends	(1,160)	(1,115)
Limitations under IRC Sec 382	(11,169)	(13,812)
Other	(1,478)us-gaap_DeferredTaxLiabilitiesOther	(1,376)us-gaap_DeferredTaxLiabilitiesOther
Gross deferred tax liabilities	(36,652)us-gaap_DeferredTaxLiabilities	(40,327)us-gaap_DeferredTaxLiabilities
Net deferred tax asset, included in other assets	$ 40,748us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 30,232us-gaap_DeferredTaxAssetsLiabilitiesNet

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses on available-for-sale securities.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets including goodwill.

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