Note 7 - Restricted Investment in Stock (Details Textual)	6 Months Ended
	Jun. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($)
Investment Holdings [Line Items]
Restricted investment in stocks	$ 2,668,000	$ 1,501,000
Other than temporary impairment charge of restricted investment	0
Investment in Federal Home Loan Bank Stock [Member]
Investment Holdings [Line Items]
Restricted investment in stocks	2,656,000
Investment in Atlantic Community Bankers Bank Stock [Member]
Investment Holdings [Line Items]
Restricted investment in stocks	12,000
VISA Class B Stock [Member]
Investment Holdings [Line Items]
Restricted investment in stocks	$ 0
Number of shares owned | shares	6,502
VISA Class A Stock [Member]
Investment Holdings [Line Items]
Conversion factor per share	1.6298