Note 5 - Investment Securities - Trust Preferred Securities (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Amortized Cost	$ 522,185	$ 475,587
Investment securities available for sale, at fair value	502,021	464,430
Unrealized Losses	(20,265)	(11,320)
Cumulative OTTI Life to Date	$ 274	$ 274	$ 454	$ 937
TPREF Funding II [Member]
Class / Tranche	Class B Notes
Amortized Cost	$ 725
Investment securities available for sale, at fair value	547
Unrealized Losses	$ (178)
Lowest Credit Rating Assigned	C
Number of Banks Currently Performing	19
Deferrals / Defaults as % of Current Balance	26.00%
Conditional Default Rates for 2018 and beyond	0.33%
Cumulative OTTI Life to Date	$ 274

Represents the class and trance of trust preferred securities.

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Represents conditional default rates for 2017 and beyond.

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Represents the current number of deferrals and defaults as a percentage of the current collateral balance.

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Represents the number of banks currently performing.

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Amount, before tax, of unrealized loss 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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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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Amount 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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Description of the credit rating indicative of likelihood of repayment of the debt instrument given by a credit rating agency (for example, Standard and Poor's, Moody's, Fitch).

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The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

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