Note 4 - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value (Details) $ in Thousands	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Corporate Debt Securities [Member]
Count	12	12
Fair Value	$ 85,282	$ 85,563
Unrealized Losses	4,718	4,436
Less Than 12 Months - Fair Value	52,559	76,218
Less Than 12 Months - Unrealized Losses	2,441	3,782
12 Months or More - Fair Value	32,723	9,345
12 Months or More - Unrealized Losses	$ 2,277	$ 654
Collateralized Debt Obligations [Member]
Count	6	7
Fair Value	$ 45,861	$ 52,898
Unrealized Losses	170	327
Less Than 12 Months - Fair Value	45,861	52,898
Less Than 12 Months - Unrealized Losses	170	327
12 Months or More - Fair Value
12 Months or More - Unrealized Losses
Other Debt Obligations [Member]
Count	1	1
Fair Value	$ 298	$ 298
Unrealized Losses	2	2
Less Than 12 Months - Fair Value
Less Than 12 Months - Unrealized Losses
12 Months or More - Fair Value	298	298
12 Months or More - Unrealized Losses	$ 2	$ 2
Available for Sale Securities Excluding Mortgage Backed Securities [Member]
Count	19	20
Fair Value	$ 131,441	$ 138,759
Unrealized Losses	4,890	4,765
Less Than 12 Months - Fair Value	98,420	129,116
Less Than 12 Months - Unrealized Losses	2,611	4,109
12 Months or More - Fair Value	33,021	9,643
12 Months or More - Unrealized Losses	$ 2,279	$ 656
REMIC and CMO [Member]
Count	8	33
Fair Value	$ 45,906	$ 238,132
Unrealized Losses	452	3,147
Less Than 12 Months - Fair Value	11,004	182,010
Less Than 12 Months - Unrealized Losses	61	1,642
12 Months or More - Fair Value	34,902	56,122
12 Months or More - Unrealized Losses	$ 391	$ 1,505
FNMA [Member]
Count	1	20
Fair Value	$ 7,084	$ 102,225
Unrealized Losses	37	1,762
Less Than 12 Months - Fair Value		75,769
Less Than 12 Months - Unrealized Losses		1,043
12 Months or More - Fair Value	7,084	26,456
12 Months or More - Unrealized Losses	$ 37	$ 719
GNMA [Member]
Count		1
Fair Value		$ 6,977
Unrealized Losses		139
Less Than 12 Months - Fair Value		6,977
Less Than 12 Months - Unrealized Losses		139
12 Months or More - Fair Value
12 Months or More - Unrealized Losses
Collateralized Mortgage Backed Securities [Member]
Count	9	57
Fair Value	$ 52,990	$ 362,049
Unrealized Losses	489	5,147
Less Than 12 Months - Fair Value	11,004	279,471
Less Than 12 Months - Unrealized Losses	61	2,923
12 Months or More - Fair Value	41,986	82,578
12 Months or More - Unrealized Losses	$ 428	$ 2,224
FHLMC [Member]
Count		3
Fair Value		$ 14,715
Unrealized Losses		99
Less Than 12 Months - Fair Value		14,715
Less Than 12 Months - Unrealized Losses		99
12 Months or More - Fair Value
12 Months or More - Unrealized Losses
Count	28	77
Fair Value	$ 184,431	$ 500,808
Unrealized Losses	5,379	9,912
Less Than 12 Months - Fair Value	109,424	408,587
Less Than 12 Months - Unrealized Losses	2,672	7,032
12 Months or More - Fair Value	75,007	92,221
12 Months or More - Unrealized Losses	$ 2,707	$ 2,880