Note 16 - Stock-based Compensation (Details Textual)	3 Months Ended		6 Months Ended
Note 16 - Stock-based Compensation (Details Textual)	Jun. 30, 2017 USD ($) shares	Jun. 30, 2016 USD ($) shares	Jun. 30, 2017 USD ($) shares	Jun. 30, 2016 USD ($) shares	Dec. 31, 2016 shares	Dec. 31, 2015 shares
Number of Share Based Compensation Plans	2		2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	142,950	154,000	142,950	154,000	147,750	165,750
Allocated Share-based Compensation Expense \| $	$ 7,952	$ 11,783	$ 18,997	$ 23,563
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			0
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				5,200
The 1997 Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	18,250		18,250
The 2008 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	124,700		124,700
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	7,165		7,165
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	804,150		804,150
The 2008 Plan [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			10 years
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized \| $	$ 67,249		$ 67,249
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			2 years 273 days
The 2008 Plan [Member] \| Employee Stock Option [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			1 year
The 2008 Plan [Member] \| Employee Stock Option [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			5 years
The 2008 Plan [Member] \| Restricted Stock [Member]
Allocated Share-based Compensation Expense \| $	9,524	$ 9,687	$ 19,048	$ 18,566
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized \| $	$ 43,251		$ 43,251
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			3 years 273 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			0
The 2008 Plan [Member] \| Restricted Stock [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				4 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				3,000
The 2008 Plan [Member] \| Restricted Stock [Member] \| Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				5 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				2,200

FIRST SOUTH BANCORP INC /VA/ 10-Q