Note 3 - Investment Securities Available for Sale (Details) - Investment Securities Available-for-Sale in an Unrealized Loss Position (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Agency RMBs [Member]
Note 3 - Investment Securities Available for Sale (Details) - Investment Securities Available-for-Sale in an Unrealized Loss Position [Line Items]
Carrying Value Less Than 12 Months	$ 7,179	$ 332,519
Gross Unrealized Losses Less Than 12 Months	(59)	(11,423)
Carrying Value Greater Than 12 Months	660,835	398,325
Gross Unrealized Losses Greater Than 12 Months	(19,305)	(20,582)
Carrying Value Total	668,014	730,844
Gross Unrealized Losses Total	(19,364)	(32,005)
Non-Agency RMBS [Member]
Note 3 - Investment Securities Available for Sale (Details) - Investment Securities Available-for-Sale in an Unrealized Loss Position [Line Items]
Carrying Value Greater Than 12 Months	1,017	1,104
Gross Unrealized Losses Greater Than 12 Months	(167)	(188)
Carrying Value Total	1,017	1,104
Gross Unrealized Losses Total	(167)	(188)
Total [Member]
Note 3 - Investment Securities Available for Sale (Details) - Investment Securities Available-for-Sale in an Unrealized Loss Position [Line Items]
Carrying Value Less Than 12 Months	7,179	332,519
Gross Unrealized Losses Less Than 12 Months	(59)	(11,423)
Carrying Value Greater Than 12 Months	661,852	399,429
Gross Unrealized Losses Greater Than 12 Months	(19,472)	(20,770)
Carrying Value Total	669,031	731,948
Gross Unrealized Losses Total	$ (19,531)	$ (32,193)