Note 3 - Available-for-sale Securities - Investment Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Available-for-sale securities in continuous loss position, less than 12 months, fair value	$ 2,972	$ 8,024
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss	(23)	(38)
Available-for-sale securities in continuous loss position, 12 months or more, fair value	16,606	18,396
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss	(1,274)	(1,184)
Available-for-sale securities in continuous loss position, fair value	19,578	26,420
Available-for-sale securities in continuous loss position, unrealized loss	(1,297)	(1,222)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities in continuous loss position, less than 12 months, fair value	2,972	8,024
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss	(23)	(38)
Available-for-sale securities in continuous loss position, 12 months or more, fair value	3,778	5,422
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss	(102)	(158)
Available-for-sale securities in continuous loss position, fair value	6,750	13,446
Available-for-sale securities in continuous loss position, unrealized loss	(125)	(196)
Corporate Debt Securities [Member]
Available-for-sale securities in continuous loss position, less than 12 months, fair value
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss
Available-for-sale securities in continuous loss position, 12 months or more, fair value	12,828	12,974
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss	(1,172)	(1,026)
Available-for-sale securities in continuous loss position, fair value	12,828	12,974
Available-for-sale securities in continuous loss position, unrealized loss	$ (1,172)	$ (1,026)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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