ServisFirst Bancshares, Inc. Annual report pursuant to Section 13 and 15(d)

PARTICIPATION IN THE SMALL BUSINESS LENDING FUND OF THE U.S. TREASURY DEPARTMENT (Additional Information) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Jun. 21, 2011	Dec. 31, 2014	Dec. 31, 2013
Fund Established Under Small Business Job Act 2010		$ 30,000,000,000
Qualified Community Banks		10,000,000,000sfbs_QualifiedCommunityBanks
Second Through Tenth Dividend Periods [Member]
Preferred Stock, Dividend Rate, Percentage	5.00%
Second Through Tenth Dividend Periods [Member] \| Minimum [Member]
Preferred Stock, Dividend Rate, Percentage	1.00%
Eleventh Through First Half Of Nineteenth Dividend [Member] \| Minimum [Member]
Preferred Stock, Dividend Rate, Percentage	1.00%
Eleventh Through First Half Of Nineteenth Dividend [Member] \| Maximum [Member]
Preferred Stock, Dividend Rate, Percentage	7.00%
Fixed Rate [Member] \| More Than Four and One Half Years [Member]
Preferred Stock, Dividend Rate, Percentage	9.00%
Qualified Small Business Lending [Member]
Preferred Stock, Dividend Rate, Percentage	1.00%
Senior Non Cumulative Perpetual Preferred Stock [Member]
Preferred Stock, Shares Issued		40,000
Preferred Stock, Liquidation Preference Per Share		$ 1,000
Preferred Stock, Liquidation Preference, Value		40,000,000
Series Preferred Stock [Member]
Preferred Stock, Shares Issued			40,000	40,000
Preferred Stock, Liquidation Preference Per Share			$ 1,000	$ 1,000
Preferred Stock, Liquidation Preference, Value		$ 25,000,000	$ 1,000,000	$ 1,000,000