Note 2 - Investment Debt Securities by Contractual Maturity (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
U.S. Government agency mortgage-backed securities, amortized cost	$ 12,170,000
U.S. Government agency mortgage-backed securities, fair value	12,139,000
Available-for-sale securities, amortized cost	12,170,000	$ 13,625,000
Available-for-sale securities	12,139,000	13,413,000
Due after five years through ten years, amortized cost	11,000,000
Due after five years through ten years, fair value	10,898,000
Available-for-sale securities, amortized cost	23,170,000	29,625,000
Available-for-sale securities	$ 23,037,000	$ 29,377,000