Note 6 - Investment Securities (Details) - Temporarily Impaired Securities (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2014
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	$ 877,208	$ 267,395
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	64,562	180
Securities Available-for-Sale - 12 Months or longer - Fair Value	106,378	621,362
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	5,246	22,494
Securities Available-for-Sale - Fair Value	983,586	888,757
Securities Available-for-Sale - Unrealized Losses	69,808	22,674
Total investment securities	877,208
Total investment securities	64,562
Total investment securities	106,378
Total investment securities	5,246
Total investment securities	983,586
Total investment securities	69,808
US Treasury Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	75,064	174,959
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	1	29
Securities Available-for-Sale - Fair Value	75,064	174,959
Securities Available-for-Sale - Unrealized Losses	1	29
Collateralized Mortgage Backed Securities [Member]
Securities Available-for-Sale
Securities Available-for-Sale - Less than 12 Months - Fair Value	792,012	92,436
Securities Available-for-Sale - Less than 12 Months - Unrealized Losses	64,526	151
Securities Available-for-Sale - 12 Months or longer - Fair Value	272	551,854
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	2	20,922
Securities Available-for-Sale - Fair Value	792,284	644,290
Securities Available-for-Sale - Unrealized Losses	64,528	21,073
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	301	46
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	50	34
Securities Available-for-Sale - Fair Value	369	46
Securities Available-for-Sale - Unrealized Losses	54	34
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	100,081	63,645
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	4,919	1,355
Securities Available-for-Sale - Fair Value	110,051	63,645
Securities Available-for-Sale - Unrealized Losses	4,949	1,355
Mutual Funds [Member]
Securities Available-for-Sale
Securities Available-for-Sale - 12 Months or longer - Fair Value	5,724	5,817
Securities Available-for-Sale - 12 Months or longer - Unrealized Losses	275	183
Securities Available-for-Sale - Fair Value	5,724	5,817
Securities Available-for-Sale - Unrealized Losses	275	183
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