Note 7 - Accruing Troubled Debt Restructurings (Details) - Accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	$ 8,464		$ 8,298
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications, Recorded Investment
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	1,485		10,024
Commercial Portfolio Segment [Member] | Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications, Recorded Investment			1,726
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications, Recorded Investment	9,949
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	26,256		16,701
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications, Recorded Investment	6,006		6,045
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	22,542		56,546
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications, Recorded Investment			33,800
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications, Recorded Investment	54,804
Real Estate Construction Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment
Real Estate Construction Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications, Recorded Investment
Real Estate Construction Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment			5,696
Real Estate Construction Portfolio Segment [Member] | Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications, Recorded Investment			5,696
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	5,301		5,201
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications, Recorded Investment	993		999
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	3,661		9,414
Residential Portfolio Segment [Member] | Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications, Recorded Investment			3,214
Residential Portfolio Segment [Member]
Financing Receivable, Modifications, Recorded Investment	9,955
Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	40,021		30,200
Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications, Recorded Investment	6,999		7,044
Rate Reduction and Payment Deferral [Member]
Financing Receivable, Modifications, Recorded Investment	27,688		81,680
Rate Reduction and Forgiveness of Principal [Member]
Financing Receivable, Modifications, Recorded Investment			44,436
Financing Receivable, Modifications, Recorded Investment	$ 74,708	$ 90,172	$ 81,680	$ 100,011	$ 100,393	$ 104,356