Note 2 - Securities (Details) - Available-for-sale Securities - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Note 2 - Securities (Details) - Available-for-sale Securities [Line Items]
Amortized cost	$ 498,633	$ 509,276
Unrealized gains	6,792	5,829
Unrealized losses	1,059	2,049
Fair value	504,366	513,056
US Treasury Securities [Member]
Note 2 - Securities (Details) - Available-for-sale Securities [Line Items]
Amortized cost	100,000	70,000
Fair value	100,000	70,000
US Government-sponsored Enterprises Debt Securities [Member]
Note 2 - Securities (Details) - Available-for-sale Securities [Line Items]
Amortized cost	184,258	203,531
Unrealized gains	2,746	2,017
Unrealized losses	194	562
Fair value	186,810	204,986
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 2 - Securities (Details) - Available-for-sale Securities [Line Items]
Amortized cost	152,552	173,573
Unrealized gains	2,564	2,042
Unrealized losses	769	1,345
Fair value	154,347	174,270
US States and Political Subdivisions Debt Securities [Member]
Note 2 - Securities (Details) - Available-for-sale Securities [Line Items]
Amortized cost	61,067	61,416
Unrealized gains	1,482	1,560
Unrealized losses	41	142
Fair value	62,508	62,834
Common Stock [Member]
Note 2 - Securities (Details) - Available-for-sale Securities [Line Items]
Amortized cost	756	756
Unrealized gains		210
Unrealized losses	55
Fair value	$ 701	$ 966

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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 gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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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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