Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions	64	115
Available for sale securities, less than 12 months, fair value	$ 460,371	$ 424,716
Available for sale securities, less than 12 months, unrealized losses	(1,922)	(14,322)
Available for sale securities, 12 months or longer, number of positions	71	21
Available for sale securities, 12 months or longer, fair value	268,248	59,930
Available for sale securities, 12 months or longer, unrealized losses	(12,139)	(2,934)
Available for sale securities, total, number of positions	135	136
Available for sale securities, total, fair value	728,619	484,646
Available for sale securities, total, unrealized losses	(14,061)	(17,256)
Held to maturity securities, less than 12 months, number of positions	32	586
Held to maturity securities, less than 12 months, fair value	84,354	610,771
Held to maturity securities, less than 12 months, unrealized losses	(880)	(20,688)
Held to maturity securities, 12 months or longer, number of positions	205	70
Held to maturity securities, 12 months or longer, fair value	297,590	78,939
Held to maturity securities, 12 months or longer, unrealized losses	(6,858)	(7,209)
Held to maturity securities, total, number of positions	237	656
Held to maturity securities, total, fair value	381,944	689,710
Held to maturity securities, total, unrealized losses	(7,738)	(27,897)
US Government-sponsored Enterprises Debt Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions	24	15
Available for sale securities, less than 12 months, fair value	358,842	91,669
Available for sale securities, less than 12 months, unrealized losses	(1,103)	(663)
Available for sale securities, 12 months or longer, number of positions	1
Available for sale securities, 12 months or longer, fair value	9,943
Available for sale securities, 12 months or longer, unrealized losses	(57)
Available for sale securities, total, number of positions	25	15
Available for sale securities, total, fair value	368,785	91,669
Available for sale securities, total, unrealized losses	(1,160)	(663)
Held to maturity securities, less than 12 months, number of positions	1	1
Held to maturity securities, less than 12 months, fair value	1,164	1,597
Held to maturity securities, less than 12 months, unrealized losses		(4)
Held to maturity securities, total, number of positions	1	1
Held to maturity securities, total, fair value	1,164	1,597
Held to maturity securities, total, unrealized losses		(4)
Residential Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions		3
Available for sale securities, less than 12 months, fair value		864
Available for sale securities, less than 12 months, unrealized losses		(15)
Available for sale securities, 12 months or longer, number of positions	2
Available for sale securities, 12 months or longer, fair value	828
Available for sale securities, 12 months or longer, unrealized losses	(20)
Available for sale securities, total, number of positions	2	3
Available for sale securities, total, fair value	828	864
Available for sale securities, total, unrealized losses	(20)	(15)
Held to maturity securities, less than 12 months, number of positions	2	13
Held to maturity securities, less than 12 months, fair value	9,658	38,396
Held to maturity securities, less than 12 months, unrealized losses	(48)	(616)
Held to maturity securities, 12 months or longer, number of positions	2	1
Held to maturity securities, 12 months or longer, fair value	3,320	392
Held to maturity securities, 12 months or longer, unrealized losses	(38)	(8)
Held to maturity securities, total, number of positions	4	14
Held to maturity securities, total, fair value	12,978	38,788
Held to maturity securities, total, unrealized losses	(86)	(624)
Commercial Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions		1
Available for sale securities, less than 12 months, fair value		1,072
Available for sale securities, less than 12 months, unrealized losses		(5)
Available for sale securities, 12 months or longer, number of positions	2
Available for sale securities, 12 months or longer, fair value	1,822
Available for sale securities, 12 months or longer, unrealized losses	(7)
Available for sale securities, total, number of positions	2	1
Available for sale securities, total, fair value	1,822	1,072
Available for sale securities, total, unrealized losses	(7)	(5)
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions	8	35
Available for sale securities, less than 12 months, fair value	2,783	17,516
Available for sale securities, less than 12 months, unrealized losses	(46)	(222)
Available for sale securities, 12 months or longer, number of positions	21	11
Available for sale securities, 12 months or longer, fair value	6,460	3,214
Available for sale securities, 12 months or longer, unrealized losses	(151)	(101)
Available for sale securities, total, number of positions	29	46
Available for sale securities, total, fair value	9,243	20,730
Available for sale securities, total, unrealized losses	(197)	(323)
Held to maturity securities, less than 12 months, number of positions	14	530
Held to maturity securities, less than 12 months, fair value	10,434	355,797
Held to maturity securities, less than 12 months, unrealized losses	(45)	(14,893)
Held to maturity securities, 12 months or longer, number of positions	180	64
Held to maturity securities, 12 months or longer, fair value	162,095	64,427
Held to maturity securities, 12 months or longer, unrealized losses	(2,864)	(6,774)
Held to maturity securities, total, number of positions	194	594
Held to maturity securities, total, fair value	172,529	420,224
Held to maturity securities, total, unrealized losses	(2,909)	(21,667)
Residential Collateralized Mortgage Obligations [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions		34
Available for sale securities, less than 12 months, fair value		187,848
Available for sale securities, less than 12 months, unrealized losses		(12,326)
Available for sale securities, 12 months or longer, number of positions	38	6
Available for sale securities, 12 months or longer, fair value	209,504	40,575
Available for sale securities, 12 months or longer, unrealized losses	(11,400)	(2,398)
Available for sale securities, total, number of positions	38	40
Available for sale securities, total, fair value	209,504	228,423
Available for sale securities, total, unrealized losses	(11,400)	(14,724)
Held to maturity securities, less than 12 months, number of positions	15	42
Held to maturity securities, less than 12 months, fair value	63,098	214,981
Held to maturity securities, less than 12 months, unrealized losses	(787)	(5,175)
Held to maturity securities, 12 months or longer, number of positions	23	5
Held to maturity securities, 12 months or longer, fair value	132,175	14,120
Held to maturity securities, 12 months or longer, unrealized losses	(3,956)	(427)
Held to maturity securities, total, number of positions	38	47
Held to maturity securities, total, fair value	195,273	229,101
Held to maturity securities, total, unrealized losses	(4,743)	(5,602)
Asset-backed Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions	1	1
Available for sale securities, less than 12 months, fair value	5,030	5,002
Available for sale securities, less than 12 months, unrealized losses	(1)	(1)
Available for sale securities, 12 months or longer, number of positions	1	1
Available for sale securities, 12 months or longer, fair value	3,609	4,475
Available for sale securities, 12 months or longer, unrealized losses	(34)	(100)
Available for sale securities, total, number of positions	2	2
Available for sale securities, total, fair value	8,639	9,477
Available for sale securities, total, unrealized losses	(35)	(101)
Domestic Corporate Debt Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions	31	25
Available for sale securities, less than 12 months, fair value	93,716	117,751
Available for sale securities, less than 12 months, unrealized losses	(772)	(1,087)
Available for sale securities, 12 months or longer, number of positions	5	2
Available for sale securities, 12 months or longer, fair value	34,218	9,824
Available for sale securities, 12 months or longer, unrealized losses	(334)	(177)
Available for sale securities, total, number of positions	36	27
Available for sale securities, total, fair value	127,934	127,575
Available for sale securities, total, unrealized losses	(1,106)	(1,264)
Other Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, 12 months or longer, number of positions	1	1
Available for sale securities, 12 months or longer, fair value	1,864	1,842
Available for sale securities, 12 months or longer, unrealized losses	(136)	(158)
Available for sale securities, total, number of positions	1	1
Available for sale securities, total, fair value	1,864	1,842
Available for sale securities, total, unrealized losses	(136)	(158)
US Treasury Securities [Member]
Note 3 - Investment Securities (Details) - Gross Unrealized Losses - Investments [Line Items]
Available for sale securities, less than 12 months, number of positions		1
Available for sale securities, less than 12 months, fair value		2,994
Available for sale securities, less than 12 months, unrealized losses		(3)
Available for sale securities, total, number of positions		1
Available for sale securities, total, fair value		2,994
Available for sale securities, total, unrealized losses		$ (3)