Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale [Line Items]
Amortized Cost	$ 421,645	$ 377,933
Gross Unrealized gains	5,094	7,087
Gross unrealized losses	3,030	2,677
Estimated fair value	423,709	382,343	$ 378,990
US Government Agencies Debt Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale [Line Items]
Amortized Cost	59,360	29,434
Gross Unrealized gains	637	500
Gross unrealized losses	294	40
Estimated fair value	59,703	29,894
Residential Mortgage Backed Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale [Line Items]
Amortized Cost	256,196	241,120
Gross Unrealized gains	1,517	1,716
Gross unrealized losses	2,050	2,516
Estimated fair value	255,663	240,320
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale [Line Items]
Amortized Cost	90,593	106,983
Gross Unrealized gains	2,872	4,850
Gross unrealized losses	627	121
Estimated fair value	92,838	111,712
Corporate Debt Securities [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale [Line Items]
Amortized Cost	15,100
Gross unrealized losses	59
Estimated fair value	15,041
Equity Investment Other [Member]
Note 3 - Investment Securities Available-for-Sale (Details) - Securities Available-for-sale [Line Items]
Amortized Cost	396	396
Gross Unrealized gains	68	21
Estimated fair value	$ 464	$ 417

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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