REGULATORY MATTERS (The Company's And Bank's Actual Capital Amounts And Ratios) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Servisfirst Bank [Member]
Total Capital to Risk Weighted Assets, Actual Amount	$ 397,748	$ 341,256
Total Capital to Risk Weighted Assets, Actual Ratio	11.62%	11.64%
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes, Amount	273,939	234,601
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Total Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	342,424	293,252
Total Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier I Capital to Risk Weighted Assets, Actual Amount	362,119	310,593
Tier I Capital to Risk Weighted Assets, Actual Ratio	10.58%	10.59%
Tier I Capital to Risk Weighted Assets, For Capital Adequacy Purposes, Amount	136,970	117,301
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.00%	4.00%
Tier I Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	205,454	175,951
Tier I Capital to Risk Weighted Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier I Capital to Average Assets, Actual Amount	362,119	310,593
Tier I Capital to Average Assets, Actual Ratio	8.92%	8.98%
Tier I Capital to Average Assets, For Capital Adequacy Purposes, Amount	162,375	138,331
Tier I Capital to Average Assets, For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier I Capital to Average Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	202,969	172,913
Tier I Capital to Average Assets, To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%
Consolidated Entities [Member]
Total Capital to Risk Weighted Assets, Actual Amount	458,073	343,904
Total Capital to Risk Weighted Assets, Actual Ratio	13.38%	11.73%
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes, Amount	273,943	234,617
Total Capital to Risk Weighted Assets, For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Tier I Capital to Risk Weighted Assets, Actual Amount	402,471	293,301
Tier I Capital to Risk Weighted Assets, Actual Ratio	11.75%	10.00%
Tier I Capital to Risk Weighted Assets, For Capital Adequacy Purposes, Amount	136,972	117,308
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.00%	4.00%
Tier I Capital to Average Assets, Actual Amount	402,471	293,301
Tier I Capital to Average Assets, Actual Ratio	9.91%	8.48%
Tier I Capital to Average Assets, For Capital Adequacy Purposes, Amount	$ 162,377	$ 138,373
Tier I Capital to Average Assets, For Capital Adequacy Purposes, Ratio	4.00%	4.00%