Note 20 - Stockholders' Equity (Details) - Company’s Significant Subsidiaries: (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Simmons First National Corporation [Member]
Total Risk-Based Capital Ratio
Total Risk-Based Capital Ratio - Actual Amount (in Dollars)	$ 380,347	$ 401,601
Total Risk-Based Capital Ratio - Actual Ratio %	14.10%	20.30%
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	215,800	158,266
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	8.00%	8.00%
Tier 1 Risk-Based Capital Ratio
Tier 1 Risk-Based Capital Ratio - Actual Amount (in Dollars)	351,334	376,839
Tier 1 Risk-Based Capital Ratio - Actual Ratio %	13.00%	19.10%
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	108,103	78,919
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Leverage Ratio
Tier 1 Leverage Ratio - Actual Amount (in Dollars)	351,334	376,839
Tier 1 Leverage Ratio - Actual Ratio %	9.20%	10.80%
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	152,754	139,570
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Simmons First National Bank [Member]
Total Risk-Based Capital Ratio
Total Risk-Based Capital Ratio - Actual Amount (in Dollars)	275,961	181,760
Total Risk-Based Capital Ratio - Actual Ratio %	14.80%	17.20%
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	149,168	84,540
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	8.00%	8.00%
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	186,460	105,674
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	10.00%	10.00%
Tier 1 Risk-Based Capital Ratio
Tier 1 Risk-Based Capital Ratio - Actual Amount (in Dollars)	261,318	171,522
Tier 1 Risk-Based Capital Ratio - Actual Ratio %	14.00%	16.30%
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	74,662	42,091
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	111,993	63,137
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	6.00%	6.00%
Tier 1 Leverage Ratio
Tier 1 Leverage Ratio - Actual Amount (in Dollars)	261,318	171,522
Tier 1 Leverage Ratio - Actual Ratio %	10.10%	8.30%
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	103,492	82,661
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	129,365	103,327
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	5.00%	5.00%
Simmons First Bank of Northwest Arkansas [Member]
Total Risk-Based Capital Ratio
Total Risk-Based Capital Ratio - Actual Amount (in Dollars)	37,701	36,084
Total Risk-Based Capital Ratio - Actual Ratio %	14.30%	13.70%
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	21,091	21,071
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	8.00%	8.00%
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	26,364	26,339
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	10.00%	10.00%
Tier 1 Risk-Based Capital Ratio
Tier 1 Risk-Based Capital Ratio - Actual Amount (in Dollars)	34,413	33,053
Tier 1 Risk-Based Capital Ratio - Actual Ratio %	13.00%	12.60%
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	10,589	10,493
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	15,883	15,740
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	6.00%	6.00%
Tier 1 Leverage Ratio
Tier 1 Leverage Ratio - Actual Amount (in Dollars)	34,413	33,053
Tier 1 Leverage Ratio - Actual Ratio %	9.80%	9.60%
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	14,046	13,772
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	17,558	17,215
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	5.00%	5.00%
Simmons First Bank of Russellville [Member]
Total Risk-Based Capital Ratio
Total Risk-Based Capital Ratio - Actual Amount (in Dollars)	19,435	18,602
Total Risk-Based Capital Ratio - Actual Ratio %	17.30%	15.60%
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	8,987	9,539
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	8.00%	8.00%
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	11,234	11,924
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	10.00%	10.00%
Tier 1 Risk-Based Capital Ratio
Tier 1 Risk-Based Capital Ratio - Actual Amount (in Dollars)	18,028	17,102
Tier 1 Risk-Based Capital Ratio - Actual Ratio %	16.10%	14.30%
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	4,479	4,784
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	6,719	7,176
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	6.00%	6.00%
Tier 1 Leverage Ratio
Tier 1 Leverage Ratio - Actual Amount (in Dollars)	18,028	17,102
Tier 1 Leverage Ratio - Actual Ratio %	10.10%	9.40%
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	7,140	7,277
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	8,925	9,097
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	5.00%	5.00%
Simmons First Bank of El Dorado [Member]
Total Risk-Based Capital Ratio
Total Risk-Based Capital Ratio - Actual Amount (in Dollars)	20,143	19,534
Total Risk-Based Capital Ratio - Actual Ratio %	19.20%	19.00%
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	8,393	8,225
Total Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	8.00%	8.00%
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	10,491	10,281
Total Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	10.00%	10.00%
Tier 1 Risk-Based Capital Ratio
Tier 1 Risk-Based Capital Ratio - Actual Amount (in Dollars)	18,825	18,409
Tier 1 Risk-Based Capital Ratio - Actual Ratio %	17.90%	17.90%
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	4,207	4,114
Tier 1 Risk-Based Capital Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	6,310	6,171
Tier 1 Risk-Based Capital Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	6.00%	6.00%
Tier 1 Leverage Ratio
Tier 1 Leverage Ratio - Actual Amount (in Dollars)	18,825	18,409
Tier 1 Leverage Ratio - Actual Ratio %	8.90%	8.30%
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Amount (in Dollars)	8,461	8,872
Tier 1 Leverage Ratio - Minimum For Capital Adequacy Purposes, Ratio %	4.00%	4.00%
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Amount (in Dollars)	$ 10,576	$ 11,090
Tier 1 Leverage Ratio - To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio %	5.00%	5.00%