Note 2 - Investment Securities - Amortized Cost and Fair Value of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Due In One Year or Less, amortized cost	$ 358
Due In One Year or Less, fair value	356
Due After One Year Through Five Years, amortized cost	4,311
Due After One Year Through Five Years, fair value	4,232
Due After Five Years Through Ten Years, amortized cost	1,134
Due After Five Years Through Ten Years, fair value	1,136
Due After Ten Years, amortized cost	1,177
Due After Ten Years, fair value	1,130
Amortized cost with single maturity date	6,980
Fair value with single maturity date	6,854
Mortgage-Backed Securities, amortized cost	326,676
Mortgage-Backed Securities, fair value	311,178
Amortized cost	333,656	$ 362,465
Fair Value	$ 318,032	$ 354,247

Amortized cost of 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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