Note 3 - Securities (Detail) - Securities Portfolio (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010
Securities available-for-sale	$ 1,009,873		$ 1,057,802
Municipal securities	76,142		81,320
Municipal securities	78,485		82,525
Trading Securities (1)	16,230	[1]	15,282	[1]
State And Municipals [Member]
Municipal securities	76,142		81,320
Municipal securities	2,343		1,205
Municipal securities	78,485		82,525
US Agency [Member]
Amortized Cost	8,122		18,000
Gross Unrealized Gains	23		7
Gross Unrealized Losses	(32)		(121)
Securities available-for-sale	8,113		17,886
Collateralized Residential Mortgage Obligations [Member]
Amortized Cost	373,600		377,692
Gross Unrealized Gains	3,824		4,261
Gross Unrealized Losses	(722)		(2,364)
Securities available-for-sale	376,702		379,589
Other Residential Mortgage Backed Securities [Member]
Amortized Cost	91,539		100,780
Gross Unrealized Gains	6,290		5,732
Gross Unrealized Losses	(24)		(61)
Securities available-for-sale	97,805		106,451
State And Municipal [Member]
Amortized Cost	471,617		512,063
Gross Unrealized Gains	10,487		4,728
Gross Unrealized Losses	(2,185)		(12,800)
Securities available-for-sale	479,919		503,991
Collateralized Debt Obligation [Member]
Amortized Cost	49,695		49,695
Gross Unrealized Losses	(33,208)		(34,837)
Securities available-for-sale	16,487		14,858
Corporate Debt [Member]
Amortized Cost	25,325		29,936
Gross Unrealized Gains	2,597		2,409
Securities available-for-sale	27,922		32,345
Hedge Fund Investment [Member]
Amortized Cost	1,231		1,245
Gross Unrealized Gains	651		438
Securities available-for-sale	1,882		1,683
Other Equity Securities [Member]
Amortized Cost	927		889
Gross Unrealized Gains	117		110
Gross Unrealized Losses	(1)
Securities available-for-sale	1,043		999
Total Equity Securities [Member]
Amortized Cost	2,158		2,134
Gross Unrealized Gains	768		548
Gross Unrealized Losses	(1)
Securities available-for-sale	2,925		2,682
Total [Member]
Amortized Cost	1,022,056		1,090,300
Gross Unrealized Gains	23,989		17,685
Gross Unrealized Losses	(36,172)		(50,183)
Securities available-for-sale	$ 1,009,873		$ 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.