Note 3 - Securities (Detail) - Securities Gains (Losses) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Proceeds from sales	$ 153,668		$ 188,556		$ 390,217
Gains (losses) on sales of securities:
Gross realized gains	3,045		4,103		18,444
Gross realized losses	(297)		(757)		(1,311)
Net realized gains on securities sales	2,748		3,346		17,133
Non-cash impairment charges:
Other-than-temporary securities impairment	(3,728)		(1,464)		(5,364)
Portion of OTTI recognized in other comprehensive (loss) income	59		528		447
Net non-cash impairment charges	(3,669)		(936)		(4,917)
Net realized (losses) gains	(921)		2,410		12,216
Income tax (benefit) expense on net realized (losses) gains	(377)		986		4,764
Net trading gains (losses) (1)	1,627	[1]	(691)	[1]	1,530	[1]
Net non-cash impairment charges:
Net non-cash impairment charges	3,669		936		4,917
Net realized (losses) gains	(921)		2,410		12,216
Collateralized Debt Obligations [Member]
Non-cash impairment charges:
Net non-cash impairment charges	(2,226)		(936)		(4,664)
Net non-cash impairment charges:
Net non-cash impairment charges	2,226		936		4,664
Other Residential Mortgage-Backed Securities [Member]
Non-cash impairment charges:
Net non-cash impairment charges	(1,443)				(86)
Net non-cash impairment charges:
Net non-cash impairment charges	1,443				86
Total [Member]
Non-cash impairment charges:
Net non-cash impairment charges	(3,669)		(936)		(4,917)
Net non-cash impairment charges:
Net non-cash impairment charges	3,669		936		4,917
Equity Securities [Member]
Non-cash impairment charges:
Net non-cash impairment charges					(167)
Net non-cash impairment charges:
Net non-cash impairment charges					$ 167

[1] All trading (losses) gains relate to trading securities still held as of December 31, 2012 and 2011.