Note 3 - Securities (Detail) - Securities Portfolio (USD $) In Thousands	Sep. 30, 2011		Dec. 31, 2010
Fair Value	$ 970,430		$ 1,057,802
Municipal securities	74,375		81,320
Municipal securities	4,577		1,205
Municipal securities	78,952		82,525
Trading Securities (1)	13,308	[1]	15,282	[1]
US Government Corporations and Agencies Securities [Member]
Amortized Cost	5,091		18,000
Gross Unrealized Gains	22		7
Gross Unrealized Losses	(10)		(121)
Fair Value	5,103		17,886
Collateralized Residential Mortgage Obligations [Member]
Amortized Cost	334,942		377,692
Gross Unrealized Gains	3,831		4,261
Gross Unrealized Losses	(1,325)		(2,364)
Fair Value	337,448		379,589
Other Residential Mortgage-Backed Securities [Member]
Amortized Cost	91,926		100,780
Gross Unrealized Gains	6,514		5,732
Gross Unrealized Losses	(53)		(61)
Fair Value	98,387		106,451
State and Municipal [Member]
Amortized Cost	467,213		512,063
Gross Unrealized Gains	18,422		4,728
Gross Unrealized Losses	(685)		(12,800)
Fair Value	484,950		503,991
Collateralized Debt Obligations [Member]
Amortized Cost	49,518		49,695
Gross Unrealized Losses	(35,301)		(34,837)
Fair Value	14,217		14,858
Corporate Debt [Member]
Amortized Cost	25,336		29,936
Gross Unrealized Gains	2,330		2,409
Fair Value	27,666		32,345
Hedge Fund Investment [Member]
Amortized Cost	1,231		1,245
Gross Unrealized Gains	389		438
Fair Value	1,620		1,683
Other Equity Securities [Member]
Amortized Cost	903		889
Gross Unrealized Gains	136		110
Fair Value	1,039		999
Total Equity Securities [Member]
Amortized Cost	2,134		2,134
Gross Unrealized Gains	525		548
Fair Value	2,659		2,682
Total [Member]
Amortized Cost	976,160		1,090,300
Gross Unrealized Gains	31,644		17,685
Gross Unrealized Losses	(37,374)		(50,183)
Fair Value	$ 970,430		$ 1,057,802

[1] Trading securities held by the Company represent diversified investment securities held in a grantor trust under deferred compensation arrangements in which plan participants may direct amounts earned to be invested in securities other than Company stock.