Note 4 - Debt and Equity Securities - Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Securities held-to-maturity, amortized cost	$ 36,406	$ 37,735
Other securities, fair value option	34,152	35,408
Securities held-to-maturity, gross unrealized gains	0	0
Securities held-to-maturity, gross unrealized losses	2,254	2,327
Securities available for sale, amortized cost	888,812	868,009
Fair Value	884,143	861,381
Gross Unrealized Gains	6,308	5,091
Gross Unrealized Losses	10,977	11,719
Corporate Debt Securities [Member]
Securities available for sale, amortized cost	110,000	110,000
Fair Value	103,694	102,910
Gross Unrealized Gains	0
Gross Unrealized Losses	6,306	7,090
Municipal Debt Securities [Member]
Securities held-to-maturity, amortized cost	36,406	37,735
Other securities, fair value option	34,152	35,408
Securities held-to-maturity, gross unrealized gains	0	0
Securities held-to-maturity, gross unrealized losses	2,254	2,327
Securities available for sale, amortized cost	124,296	124,984
Fair Value	127,281	126,903
Gross Unrealized Gains	2,985	1,983
Gross Unrealized Losses	0	64
Mutual Fund Debt Securities [Member]
Securities available for sale, amortized cost	21,431	21,366
Fair Value	21,431	21,366
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Collateralized Debt Obligations [Member]
Securities available for sale, amortized cost	85,470	85,470
Fair Value	86,438	86,365
Gross Unrealized Gains	968	895
Gross Unrealized Losses	0
Other Debt Obligations [Member]
Securities available for sale, amortized cost	7,396	7,363
Fair Value	7,394	7,361
Gross Unrealized Gains	0	0
Gross Unrealized Losses	2	2
Available for Sale Securities Excluding Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	348,593	349,183
Fair Value	346,238	344,905
Gross Unrealized Gains	3,953	2,878
Gross Unrealized Losses	6,308	7,156
REMIC and CMO [Member]
Securities available for sale, amortized cost	426,537	402,636
Fair Value	425,209	401,370
Gross Unrealized Gains	1,826	1,607
Gross Unrealized Losses	3,154	2,873
GNMA [Member]
Securities available for sale, amortized cost	1,250	1,319
Fair Value	1,352	1,427
Gross Unrealized Gains	102	108
Gross Unrealized Losses	0
FNMA [Member]
Securities available for sale, amortized cost	107,176	109,493
Fair Value	106,140	108,351
Gross Unrealized Gains	396	463
Gross Unrealized Losses	1,432	1,605
FHLMC [Member]
Securities available for sale, amortized cost	5,256	5,378
Fair Value	5,204	5,328
Gross Unrealized Gains	31	35
Gross Unrealized Losses	83	85
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	540,219	518,826
Fair Value	537,905	516,476
Gross Unrealized Gains	2,355	2,213
Gross Unrealized Losses	$ 4,669	$ 4,563

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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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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