Note 4 - Investment Securities (Detail) - Amortized Cost and Fair Value of Investment Portfolio (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Securities available-for-sale:
Securities available-for-sale - Fair Value	$ 299,073
US Government Agencies Debt Securities [Member]
Securities available-for-sale:
Securities available-for-sale - Amortized cost	517	518
Securities available-for-sale - Gross unrealized gains	61	65
Securities available-for-sale - Gross unrealized losses	0	0
Securities available-for-sale - Fair Value	578	583
US States and Political Subdivisions Debt Securities [Member]
Securities available-for-sale:
Securities available-for-sale - Amortized cost	16,227	16,258
Securities available-for-sale - Gross unrealized gains	1,449	1,727
Securities available-for-sale - Gross unrealized losses	0	0
Securities available-for-sale - Fair Value	17,676	17,986
Residential Mortgage Backed Securities [Member]
Securities available-for-sale:
Securities available-for-sale - Amortized cost	135,271	156,492
Securities available-for-sale - Gross unrealized gains	2,954	3,188
Securities available-for-sale - Gross unrealized losses	(230)	(567)
Securities available-for-sale - Fair Value	137,995	159,113
Commercial Mortgage Backed Securities [Member]
Securities available-for-sale:
Securities available-for-sale - Amortized cost	37,538	0
Securities available-for-sale - Gross unrealized gains	0	0
Securities available-for-sale - Gross unrealized losses	(710)	0
Securities available-for-sale - Fair Value	36,828	0
All Other Debt Securities [Member]
Securities available-for-sale:
Securities available-for-sale - Amortized cost	105,217	67,181
Securities available-for-sale - Gross unrealized gains	1,164	1,017
Securities available-for-sale - Gross unrealized losses	(386)	(309)
Securities available-for-sale - Fair Value	105,996	67,889
Total [Member]
Securities available-for-sale:
Securities available-for-sale - Amortized cost	294,770	240,450
Securities available-for-sale - Gross unrealized gains	5,629	5,997
Securities available-for-sale - Gross unrealized losses	(1,326)	(876)
Securities available-for-sale - Fair Value	$ 299,073	$ 245,571

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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

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-Name FASB Staff Position (FSP)

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-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

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Reference 4: 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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15C

-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

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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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.

+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details