Note 7 - Loans - Non-accrual Troubled Debt Restructurings (Details) - Non-accruing Troubled Debt Restructuring [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accruing TDRs	$ 32,779	$ 29,722	$ 23,209	$ 39,923
Payment Deferral [Member]
Accruing TDRs	15,898	17,431
Contractual Interest Rate Reduction [Member]
Accruing TDRs	1,765	1,795
Rate Reduction and Payment Deferral [Member]
Accruing TDRs	15,116	10,496
Commercial Portfolio Segment [Member]
Accruing TDRs	13,560	14,565
Commercial Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	13,560	14,565
Commercial Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Commercial Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs
Commercial Real Estate Portfolio Segment [Member]
Accruing TDRs	18,923	14,633
Commercial Real Estate Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	2,206	2,510
Commercial Real Estate Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs	1,765	1,795
Commercial Real Estate Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	14,952	10,328
Residential Portfolio Segment [Member]
Accruing TDRs	296	524
Residential Portfolio Segment [Member] | Payment Deferral [Member]
Accruing TDRs	132	356
Residential Portfolio Segment [Member] | Contractual Interest Rate Reduction [Member]
Accruing TDRs
Residential Portfolio Segment [Member] | Rate Reduction and Payment Deferral [Member]
Accruing TDRs	$ 164	$ 168