Note 7 - Non-accrual Troubled Debt Restructurings (Details) - Non-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]
Non-accrual TDRs	$ 3,114		$ 1,033
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Non-accrual TDRs	90		1,123
Commercial Portfolio Segment [Member] | Rate Reduction [Member]
Non-accrual TDRs			90
Commercial Portfolio Segment [Member]
Non-accrual TDRs	3,204
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Non-accrual TDRs	1,520		1,544
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Non-accrual TDRs	20,007		21,906
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction [Member]
Non-accrual TDRs			20,362
Commercial Real Estate Portfolio Segment [Member]
Non-accrual TDRs	21,527
Real Estate Construction Portfolio Segment [Member] | Payment Deferral [Member]
Non-accrual TDRs			9,981
Real Estate Construction Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Non-accrual TDRs			15,806
Real Estate Construction Portfolio Segment [Member] | Rate Reduction [Member]
Non-accrual TDRs			5,825
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Non-accrual TDRs	538		388
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Non-accrual TDRs	173		1,088
Residential Portfolio Segment [Member] | Rate Reduction [Member]
Non-accrual TDRs			700
Residential Portfolio Segment [Member]
Non-accrual TDRs	711
Payment Deferral [Member]
Non-accrual TDRs	5,172		12,946
Rate Reduction and Payment Deferral [Member]
Non-accrual TDRs	20,270		39,923
Rate Reduction [Member]
Non-accrual TDRs			26,977
Non-accrual TDRs	$ 25,442	$ 23,209	$ 39,923	$ 42,595	$ 44,541	$ 41,618