Note 4 - Investments - Amortized Cost and Fair Value Of Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Available for sale securities, amortized cost	$ 234,118	$ 194,681
Available for sale securities, gross unrealized gains	5,862	2,217
Available for sale securities, gross unrealized losses	(321)	(587)
Available for sale securities	239,659	196,311
Held to maturity securities	48,718	52,231
Held to maturity securities, gross unrealized gains	1,541	985
Held to maturity securities, gross unrealized losses	(30)	(86)
Held to maturity securities	50,229	53,130
US Treasury Securities [Member]
Available for sale securities, amortized cost	95,901	55,922
Available for sale securities, gross unrealized gains	518	6
Available for sale securities, gross unrealized losses		(275)
Available for sale securities	96,419	55,653
US Government Agencies Debt Securities [Member]
Available for sale securities, amortized cost	7,500	12,493
Available for sale securities, gross unrealized gains	161	93
Available for sale securities, gross unrealized losses		(16)
Available for sale securities	7,661	12,570
Held to maturity securities		5,000
Held to maturity securities, gross unrealized gains
Held to maturity securities, gross unrealized losses		(20)
Held to maturity securities		4,980
Collateralized Mortgage Backed Securities [Member]
Available for sale securities, amortized cost	99,664	104,414
Available for sale securities, gross unrealized gains	4,419	1,832
Available for sale securities, gross unrealized losses	(158)	(93)
Available for sale securities	103,925	106,153
Collateralized Mortgage Obligations [Member]
Available for sale securities, amortized cost	27,431	15,440
Available for sale securities, gross unrealized gains	744	251
Available for sale securities, gross unrealized losses	(163)	(203)
Available for sale securities	28,012	15,488
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities, amortized cost	3,622	6,412
Available for sale securities, gross unrealized gains	20	35
Available for sale securities, gross unrealized losses
Available for sale securities	3,642	6,447
Held to maturity securities	48,718	47,231
Held to maturity securities, gross unrealized gains	1,541	985
Held to maturity securities, gross unrealized losses	(30)	(66)
Held to maturity securities	$ 50,229	$ 48,150

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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