Note 7 - Loans - Accruing Troubled Debt Restructurings (Details) - Accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Accruing TDRs	$ 79,819	$ 80,419	$ 65,393	$ 74,708	$ 90,172	$ 81,680
Payment Deferral [Member]
Accruing TDRs	63,884		39,054
Contractual Interest Rate Reduction [Member]
Accruing TDRs	6,446		6,750
Rate Reduction and Payment Deferral [Member]
Accruing TDRs	9,489		19,589
Commercial Portfolio Segment [Member]
Accruing TDRs	5,794		12,052
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	5,463		7,971
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	331		4,081
Real Estate Construction Loans [Member]
Accruing TDRs	28,472
Real Estate Construction Loans [Member] | Payment Deferral [Member]
Accruing TDRs	28,472
Real Estate Construction Loans [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Real Estate Construction Loans [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs
Commercial Real Estate Portfolio Segment [Member]
Accruing TDRs	37,864		44,392
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	25,625		25,979
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	5,917		5,961
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	6,322		12,452
Residential Portfolio Segment [Member]
Accruing TDRs	7,689		8,949
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	4,324		5,104
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	529		789
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	$ 2,836		$ 3,056