Note 10 - Revenue Recognition - Noninterest Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Noninterest income (in-scope of Topic 606)		$ 879	$ 752
Noninterest income (out-of-scope of Topic 606)(1)	[1]	178	147
Total noninterest income		1,057	899
Maintenance Fees [Member]
Noninterest income (in-scope of Topic 606)		40	39
Overdraft Fees [Member]
Noninterest income (in-scope of Topic 606)		438	329
Other Fees [Member]
Noninterest income (in-scope of Topic 606)		77	69
Electronic Banking Fees [Member]
Noninterest income (in-scope of Topic 606)		$ 324	$ 315

[1] Noninterest income items that are out-of-scope include net realized gains (losses) on sales of securities, net gains (losses) on sales of loans, earnings on bank-owned life insurance and certain other noninterest income items.