Note 7 - Securities Available for Sale - Summary of Securities Available for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Securities available for sale, amortized cost	$ 84,883	$ 81,381
Investment securities available for sale, gross unrealized gains	125	1
Investment securities available for sale, gross unrealized losses	(156)	(1,523)
Securities available for sale	84,852	79,859
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	22,126	8,159
Investment securities available for sale, gross unrealized gains	78	0
Investment securities available for sale, gross unrealized losses	(17)	(136)
Securities available for sale	22,187	8,023
Other Marketable Securities [Member]
Securities available for sale, amortized cost	62,757	73,222
Investment securities available for sale, gross unrealized gains	47	1
Investment securities available for sale, gross unrealized losses	(139)	(1,387)
Securities available for sale	62,665	71,836
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale, amortized cost	13,424	3,886
Investment securities available for sale, gross unrealized gains	16	0
Investment securities available for sale, gross unrealized losses	(17)	(117)
Securities available for sale	13,423	3,769
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member] | Collateralized Mortgage Obligations [Member]
Securities available for sale, amortized cost	180	199
Investment securities available for sale, gross unrealized gains	2	0
Investment securities available for sale, gross unrealized losses	0	(9)
Securities available for sale	182	190
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale, amortized cost	8,522	4,074
Investment securities available for sale, gross unrealized gains	60	0
Investment securities available for sale, gross unrealized losses	0	(10)
Securities available for sale	8,582	4,064
US Government Agencies Debt Securities [Member] | Other Marketable Securities [Member]
Securities available for sale, amortized cost	59,978	69,971
Investment securities available for sale, gross unrealized gains	41	0
Investment securities available for sale, gross unrealized losses	(103)	(1,236)
Securities available for sale	59,916	68,735
US States and Political Subdivisions Debt Securities [Member] | Other Marketable Securities [Member]
Securities available for sale, amortized cost	1,971	2,378
Investment securities available for sale, gross unrealized gains	6	1
Investment securities available for sale, gross unrealized losses	0	(10)
Securities available for sale	1,977	2,369
Corporate Debt Securities [Member] | Other Marketable Securities [Member]
Securities available for sale, amortized cost	108	173
Investment securities available for sale, gross unrealized gains	0	0
Investment securities available for sale, gross unrealized losses	(1)	(1)
Securities available for sale	107	172
Preferred Stock [Member] | Other Marketable Securities [Member]
Securities available for sale, amortized cost	700	700
Investment securities available for sale, gross unrealized gains	0	0
Investment securities available for sale, gross unrealized losses	(35)	(140)
Securities available for sale	$ 665	$ 560