Note 7 - Investment Securities (Details) - Investment Securities - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Securities Available-for-Sale
Securities available-for-sale, amortized cost	$ 1,378,088	$ 1,324,408
Securities available-for-sale, gross unrealized gains	6,933	6,326
Securities available-for-sale, gross unrealized losses	4,142	11,799
Securities available-for-sale	1,380,879	1,318,935
US Treasury Securities [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	284,603	664,206
Securities available-for-sale, gross unrealized gains	388	63
Securities available-for-sale, gross unrealized losses		265
Securities available-for-sale	284,991	664,004
Collateralized Mortgage Backed Securities [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	1,005,527	549,296
Securities available-for-sale, gross unrealized gains	1,066	1,393
Securities available-for-sale, gross unrealized losses	2,195	6,386
Securities available-for-sale	1,004,398	544,303
Collateralized Mortgage Obligations [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	67	79
Securities available-for-sale, gross unrealized losses	29	34
Securities available-for-sale	38	45
Corporate Debt Securities [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	74,952	94,943
Securities available-for-sale, gross unrealized gains	370	776
Securities available-for-sale, gross unrealized losses	1,492	1,247
Securities available-for-sale	73,830	94,472
Mutual Funds [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	6,000	6,000
Securities available-for-sale, gross unrealized losses	101	134
Securities available-for-sale	5,899	5,866
Preferred Stock of Government Sponsored Entities [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	2,811	6,276
Securities available-for-sale, gross unrealized gains	1,706	681
Securities available-for-sale, gross unrealized losses		3,733
Securities available-for-sale	4,517	3,224
Other Equity Securities [Member]
Securities Available-for-Sale
Securities available-for-sale, amortized cost	4,128	3,608
Securities available-for-sale, gross unrealized gains	3,403	3,413
Securities available-for-sale, gross unrealized losses	325
Securities available-for-sale	$ 7,206	$ 7,021

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

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-Publisher FASB

-Name Accounting Standards Codification

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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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