Note 4 - Investment Securities (Detail) - Schedule of gross unrealized losses - investments (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Available for sale securities, less than 12 months, fair value	$ 69,909	$ 331,504
Available for sale securities, less than 12 months, unrealized losses	(1,334)	(8,496)
Available for sale securities, 12 months or longer, fair value	58,390	20,575
Available for sale securities, 12 months or longer, unrealized losses	(1,383)	(1,367)
Available for sale securities, total, fair value	128,299	352,079
Available for sale securities, total, unrealized losses	(2,717)	(9,863)
Held to maturity securities, less than 12 months, fair value	54,757	22,157
Held to maturity securities, less than 12 months, unrealized losses	(328)	(382)
Held to maturity securities, 12 months or longer, fair value	23,037	38,845
Held to maturity securities, 12 months or longer, unrealized losses	(2,344)	(2,772)
Held to maturity securities, total, fair value	77,794	61,002
Held to maturity securities, total, unrealized losses	(2,672)	(3,154)
US States and Political Subdivisions Debt Securities [Member]
Held to maturity securities, less than 12 months, fair value	22,747	22,157
Held to maturity securities, less than 12 months, unrealized losses	(193)	(382)
Held to maturity securities, 12 months or longer, fair value	7,075	18,663
Held to maturity securities, 12 months or longer, unrealized losses	(178)	(760)
Held to maturity securities, total, fair value	29,822	40,820
Held to maturity securities, total, unrealized losses	(371)	(1,142)
US States and Political Subdivisions Debt Securities [Member]
Available for sale securities, less than 12 months, fair value	8,115	132,014
Available for sale securities, less than 12 months, unrealized losses	(102)	(5,505)
Available for sale securities, 12 months or longer, fair value	22,117	10,341
Available for sale securities, 12 months or longer, unrealized losses	(369)	(542)
Available for sale securities, total, fair value	30,232	142,355
Available for sale securities, total, unrealized losses	(471)	(6,047)
Residential Collateralized Mortgage Obligations [Member]
Held to maturity securities, less than 12 months, fair value	32,010
Held to maturity securities, less than 12 months, unrealized losses	(135)
Held to maturity securities, 12 months or longer, fair value	15,962	20,182
Held to maturity securities, 12 months or longer, unrealized losses	(2,166)	(2,012)
Held to maturity securities, total, fair value	47,972	20,182
Held to maturity securities, total, unrealized losses	(2,301)	(2,012)
Residential Collateralized Mortgage Obligations [Member]
Available for sale securities, less than 12 months, fair value	18
Available for sale securities, total, fair value	18
US Government-sponsored Enterprises Debt Securities [Member]
Available for sale securities, less than 12 months, fair value	15,012	146,083
Available for sale securities, less than 12 months, unrealized losses	(42)	(2,365)
Available for sale securities, total, fair value	15,012	146,083
Available for sale securities, total, unrealized losses	(42)	(2,365)
Residential Mortgage Backed Securities [Member]
Available for sale securities, less than 12 months, fair value	2,540	1,534
Available for sale securities, less than 12 months, unrealized losses	(3)	(15)
Available for sale securities, 12 months or longer, fair value	973
Available for sale securities, 12 months or longer, unrealized losses	(3)
Available for sale securities, total, fair value	3,513	1,534
Available for sale securities, total, unrealized losses	(6)	(15)
Commercial Mortgage Backed Securities [Member]
Available for sale securities, less than 12 months, fair value		3,028
Available for sale securities, less than 12 months, unrealized losses		(23)
Available for sale securities, 12 months or longer, fair value	1,365
Available for sale securities, 12 months or longer, unrealized losses	(6)
Available for sale securities, total, fair value	1,365	3,028
Available for sale securities, total, unrealized losses	(6)	(23)
Asset-backed Securities [Member]
Available for sale securities, 12 months or longer, fair value	7,651	8,286
Available for sale securities, 12 months or longer, unrealized losses	(282)	(774)
Available for sale securities, total, fair value	7,651	8,286
Available for sale securities, total, unrealized losses	(282)	(774)
FHLMC And FNMA Stock [Member]
Available for sale securities, less than 12 months, fair value		550
Available for sale securities, less than 12 months, unrealized losses		(211)
Available for sale securities, 12 months or longer, fair value	1
Available for sale securities, 12 months or longer, unrealized losses	(5)
Available for sale securities, total, fair value	1	550
Available for sale securities, total, unrealized losses	(5)	(211)
Domestic Corporate Debt Securities [Member]
Available for sale securities, less than 12 months, fair value	44,222	44,752
Available for sale securities, less than 12 months, unrealized losses	(1,187)	(365)
Available for sale securities, 12 months or longer, fair value	24,324
Available for sale securities, 12 months or longer, unrealized losses	(676)
Available for sale securities, total, fair value	68,546	44,752
Available for sale securities, total, unrealized losses	(1,863)	(365)
Other Securities [Member]
Available for sale securities, less than 12 months, fair value	2	1
Available for sale securities, 12 months or longer, fair value	1,959	1,948
Available for sale securities, 12 months or longer, unrealized losses	(42)	(51)
Available for sale securities, total, fair value	1,961	1,949
Available for sale securities, total, unrealized losses	(42)	(51)
US Treasury Securities [Member]
Available for sale securities, less than 12 months, fair value		3,542
Available for sale securities, less than 12 months, unrealized losses		(12)
Available for sale securities, total, fair value		3,542
Available for sale securities, total, unrealized losses		$ (12)

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized neither as held-to-maturity nor trading securities.

Name:	us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses1
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the excess of amortized cost basis over fair value of securities in a loss position and which are categorized neither as held-to-maturity nor trading securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 21

-Subparagraph a

-Clause 2

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 17

-Subparagraph a

-Clause 2

-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.

+ Details

Name:	us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses1
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 21

-Subparagraph a(2)

-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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 17

-Subparagraph a(1)

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27290-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for less than twelve months for those securities which are categorized neither as held-to-maturity nor trading securities.

+ References

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 17

-Subparagraph a

-Clause 2

-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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27337-111563

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27290-111563

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 21

-Subparagraph a

-Clause 2

-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.

+ Details

Name:	us-gaap_AvailableforsaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses1
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 21

-Subparagraph a(2)

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 17

-Subparagraph a(1)

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27290-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the excess of amortized cost basis over fair value of securities in a loss position and which are categorized as held-to-maturity.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAggregateLosses
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the fair value of securities categorized as held-to-maturity which are in an unrealized loss position.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the fair value of securities categorized as held-to-maturity that have been in a continuous unrealized loss position for less than twelve months.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the fair value of securities categorized as held-to-maturity securities that have been in a continuous unrealized loss position for twelve months or longer.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant