Note 6 - Investment Securities (Details) - Temporarily Impaired Securities (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Securities Available-for-Sale
Investment Securities - Less than 12 Months - Fair Value	$ 101,154	$ 877,208
Investment Securities - Less than 12 Months - Unrealized Losses	3	64,562
Investment Securities - 12 Months or longer - Fair Value	705,820	106,378
Investment Securities- 12 Months or longer - Unrealized Losses	26,547	5,246
Investment Securities - Fair Value	806,974	983,586
Investment Securities - Unrealized Losses	26,550	69,808
US Treasury Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	99,999	75,064
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	1	1
Securities Available-for-Sale - Fair Value	99,999	75,064
Securities Available-for-Sale - Unrealized Losses	1	1
Collateralized Mortgage Backed Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	185	792,012
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	1	64,526
Securities Available-for-Sale - 12 Months or longer - Fair Value	636,390	272
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	24,896	2
Securities Available-for-Sale - Fair Value	636,575	792,284
Securities Available-for-Sale - Unrealized Losses	24,897	64,528
Collateralized Mortgage Obligations [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value		68
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses		4
Securities Available-for-Sale - 12 Months or longer - Fair Value	46	301
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	35	50
Securities Available-for-Sale - Fair Value	46	369
Securities Available-for-Sale - Unrealized Losses	35	54
Corporate Debt Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value		9,970
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses		30
Securities Available-for-Sale - 12 Months or longer - Fair Value	63,551	100,081
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	1,449	4,919
Securities Available-for-Sale - Fair Value	63,551	110,051
Securities Available-for-Sale - Unrealized Losses	1,449	4,949
Mutual Funds [Member]
Securities Available-for-Sale
Securities Available-for-Sale - 12 Months or longer - Fair Value	5,833	5,724
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	167	275
Securities Available-for-Sale - Fair Value	5,833	5,724
Securities Available-for-Sale - Unrealized Losses	167	275
Preferred Stock of Government Sponsored Entities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	970
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	1
Securities Available-for-Sale - Fair Value	970
Securities Available-for-Sale - Unrealized Losses	1
Total [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	101,154	877,208
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	3	64,562
Securities Available-for-Sale - 12 Months or longer - Fair Value	705,820	106,378
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	26,547	5,246
Securities Available-for-Sale - Fair Value	806,974	983,586
Securities Available-for-Sale - Unrealized Losses	26,550	69,808
Mortgage Backed Securities Non Agency [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value		94
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses		1
Securities Available-for-Sale - Fair Value		94
Securities Available-for-Sale - Unrealized Losses		$ 1