Note 6 - Debt and Equity Securities - Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Securities held-to-maturity, amortized cost	$ 37,735	$ 6,180
Other securities, fair value option	35,408	6,180
Securities held-to-maturity, gross unrealized gains	0	0
Securities held-to-maturity, gross unrealized losses	2,327	0
Securities available for sale, amortized cost	868,009	994,311
Fair Value	861,381	993,397
Gross Unrealized Gains	5,091	8,998
Gross Unrealized Losses	11,719	9,912
Corporate Debt Securities [Member]
Securities available for sale, amortized cost	110,000	115,976
Fair Value	102,910	111,674
Gross Unrealized Gains	0	134
Gross Unrealized Losses	7,090	4,436
Municipal Debt Securities [Member]
Securities held-to-maturity, amortized cost	37,735	6,180
Other securities, fair value option	35,408	6,180
Securities held-to-maturity, gross unrealized gains	0	0
Securities held-to-maturity, gross unrealized losses	2,327	0
Securities available for sale, amortized cost	124,984	127,696
Fair Value	126,903	131,583
Gross Unrealized Gains	1,983	3,887
Gross Unrealized Losses	64	0
Mutual Fund Debt Securities [Member]
Securities available for sale, amortized cost	21,366	21,290
Fair Value	21,366	21,290
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Collateralized Debt Obligations [Member]
Securities available for sale, amortized cost	85,470	53,225
Fair Value	86,365	52,898
Gross Unrealized Gains	895
Gross Unrealized Losses	0	327
Other Debt Obligations [Member]
Securities available for sale, amortized cost	7,363	7,214
Fair Value	7,361	7,212
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	349,183	325,401
Fair Value	344,905	324,657
Gross Unrealized Gains	2,878	4,021
Gross Unrealized Losses	7,156	4,765
REMIC and CMO [Member]
Securities available for sale, amortized cost	402,636	469,987
Fair Value	401,370	469,936
Gross Unrealized Gains	1,607	3,096
Gross Unrealized Losses	2,873	3,147
GNMA [Member]
Securities available for sale, amortized cost	1,319	11,635
Fair Value	1,427	11,798
Gross Unrealized Gains	108	302
Gross Unrealized Losses	0	139
FNMA [Member]
Securities available for sale, amortized cost	109,493	170,327
Fair Value	108,351	170,057
Gross Unrealized Gains	463	1,492
Gross Unrealized Losses	1,605	1,762
FHLMC [Member]
Securities available for sale, amortized cost	5,378	16,961
Fair Value	5,328	16,949
Gross Unrealized Gains	35	87
Gross Unrealized Losses	85	99
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	518,826	668,910
Fair Value	516,476	668,740
Gross Unrealized Gains	2,213	4,977
Gross Unrealized Losses	$ 4,563	$ 5,147

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

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