Note 4 - Investment Securities (Detail) - Schedule of amortized cost, unrealized gains and losses, and fair value - held to maturity investment securities portfolio (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Amortized Cost	$ 755,906	$ 580,728
Gross Unrealized Gains	25,096	17,137
Gross Unrealized Losses	(2,672)	(3,154)
Fair Value	778,330	594,711
Residential Mortgage Backed Securities [Member]
Amortized Cost	34,072	40,531
Gross Unrealized Gains	1,646	1,797
Fair Value	35,718	42,328
US States and Political Subdivisions Debt Securities [Member]
Amortized Cost	513,823	455,372
Gross Unrealized Gains	20,045	13,142
Gross Unrealized Losses	(371)	(1,142)
Fair Value	533,497	467,372
Residential Collateralized Mortgage Obligations [Member]
Amortized Cost	208,011	84,825
Gross Unrealized Gains	3,405	2,198
Gross Unrealized Losses	(2,301)	(2,012)
Fair Value	$ 209,115	$ 85,011

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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Reference 12: http://www.xbrl.org/2003/role/presentationRef

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+ Details