Note 8 - Loans (Details) - Accruing Troubled Debt Restructurings - Accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Modifications [Line Items]
Accruing TDRs	$ 89,881	$ 100,011	$ 104,356	$ 123,089	$ 111,136	$ 117,597
Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	37,958		41,196
Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	7,065		26,694
Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	44,858		36,056
Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs			410
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	12,872		16,506
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	11,010		11,572
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	1,862		4,934
Real Estate Construction Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	5,713		5,765
Real Estate Construction Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs			5,765
Real Estate Construction Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	5,713
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	61,805		73,588
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	21,700		20,543
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	6,064		26,694
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	34,041		26,351
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	9,491		8,497
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	5,248		3,316
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	1,001
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs	$ 3,242		4,771
Residential Portfolio Segment [Member] | Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications [Line Items]
Accruing TDRs			$ 410