Note 4 - Amortized Cost and Fair Value of Securities (Details) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Corporate Debt Securities [Member]
Amortized Cost	$ 110,000,000	$ 115,976,000
Fair Value	106,263,000	111,674,000
Gross Unrealized Gains	981,000	134,000
Gross Unrealized Losses	4,718,000	4,436,000
Municipal Debt Securities [Member]
Amortized Cost	28,410,000	6,180,000
Other securities, fair value option	28,410,000	6,180,000
Amortized Cost	126,347,000	127,696,000
Fair Value	131,716,000	131,583,000
Gross Unrealized Gains	5,369,000	3,887,000
Gross Unrealized Losses
Mutual Fund Debt Securities [Member]
Amortized Cost	21,645,000	21,290,000
Fair Value	21,645,000	21,290,000
Gross Unrealized Gains
Gross Unrealized Losses
Collateralized Debt Obligations [Member]
Amortized Cost	101,650,000	53,225,000
Fair Value	101,820,000	52,898,000
Gross Unrealized Gains	340,000
Gross Unrealized Losses	170,000	327,000
Other Debt Obligations [Member]
Amortized Cost	7,169,000	7,214,000
Fair Value	7,167,000	7,212,000
Gross Unrealized Gains
Gross Unrealized Losses	2,000	2,000
Available for Sale Securities Excluding Mortgage Backed Securities [Member]
Amortized Cost	366,811,000	325,401,000
Fair Value	368,611,000	324,657,000
Gross Unrealized Gains	6,690,000	4,021,000
Gross Unrealized Losses	4,890,000	4,765,000
REMIC and CMO [Member]
Amortized Cost	412,117,000	469,987,000
Fair Value	420,227,000	469,936,000
Gross Unrealized Gains	8,562,000	3,096,000
Gross Unrealized Losses	452,000	3,147,000
GNMA [Member]
Amortized Cost	7,952,000	11,635,000
Fair Value	8,120,000	11,798,000
Gross Unrealized Gains	168,000	302,000
Gross Unrealized Losses		139,000
FNMA [Member]
Amortized Cost	132,981,000	170,327,000
Fair Value	136,393,000	170,057,000
Gross Unrealized Gains	3,449,000	1,492,000
Gross Unrealized Losses	37,000	1,762,000
FHLMC [Member]
Amortized Cost	15,453,000	16,961,000
Fair Value	15,760,000	16,949,000
Gross Unrealized Gains	307,000	87,000
Gross Unrealized Losses		99,000
Collateralized Mortgage Backed Securities [Member]
Amortized Cost	568,503,000	668,910,000
Fair Value	580,500,000	668,740,000
Gross Unrealized Gains	12,486,000	4,977,000
Gross Unrealized Losses	489,000	5,147,000
Amortized Cost	28,410,000	6,180,000
Other securities, fair value option	28,410,000	6,180,000
Amortized Cost	935,314,000	994,311,000
Fair Value	949,111,000	993,397,000
Gross Unrealized Gains	19,176,000	8,998,000
Gross Unrealized Losses	$ 5,379,000	$ 9,912,000