Note 14 - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Balance	$ 565,390	$ 559,559	$ 549,464	$ 538,044	$ 535,307	$ 532,608	$ 549,464	$ 532,608
Total other comprehensive loss, net of tax	(2,353)	(74)	2,210	(1,542)	(832)	(895)	(217)	(3,269)
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings						0
Impact of adoption of Accounting Standard Update 2016-01					0	0
Balance	568,392	565,390	559,559	541,756	538,044	535,307	568,392	541,756
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	(3,815)		(15,649)	(16,501)		(5,522)	(15,649)	(5,522)
Other comprehensive income before reclassifications, net of tax	(475)			(3,505)			11,349	(13,159)
Amounts reclassified from accumulated other comprehensive income, net of tax				0			10	0
Total other comprehensive loss, net of tax	(475)			(3,505)			11,359	(13,159)
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings								(1,325)
Impact of adoption of Accounting Standard Update 2016-01								0
Balance	(4,290)	(3,815)		(20,006)	(16,501)		(4,290)	(20,006)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	(6,132)		3,704	8,027		231	3,704	231
Other comprehensive income before reclassifications, net of tax	(1,664)			1,950			(10,914)	9,455
Amounts reclassified from accumulated other comprehensive income, net of tax	(282)			(80)			(868)	161
Total other comprehensive loss, net of tax	(1,946)			1,870			(11,782)	9,616
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings								50
Impact of adoption of Accounting Standard Update 2016-01								0
Balance	(8,078)	(6,132)		9,897	8,027		(8,078)	9,897
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(1,658)		(1,673)	(4,325)		(3,695)	(1,673)	(3,695)
Other comprehensive income before reclassifications, net of tax	0			0			0	0
Amounts reclassified from accumulated other comprehensive income, net of tax	7			84			22	252
Total other comprehensive loss, net of tax	7			84			22	252
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings								(798)
Impact of adoption of Accounting Standard Update 2016-01								0
Balance	(1,651)	(1,658)		(4,241)	(4,325)		(1,651)	(4,241)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Balance	989		866	792		0	866	0
Other comprehensive income before reclassifications, net of tax	61			9			184	22
Amounts reclassified from accumulated other comprehensive income, net of tax	0			0			0	0
Total other comprehensive loss, net of tax	61			9			184	22
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings								0
Impact of adoption of Accounting Standard Update 2016-01								779
Balance	1,050	989		801	792		1,050	801
AOCI Attributable to Parent [Member]
Balance	(10,616)	(10,542)	(12,752)	(12,007)	(11,179)	(8,986)	(12,752)	(8,986)
Other comprehensive income before reclassifications, net of tax	(2,078)			(1,546)			619	(3,682)
Amounts reclassified from accumulated other comprehensive income, net of tax	(275)			4			(836)	413
Total other comprehensive loss, net of tax	(2,353)	(74)	2,210	(1,542)	(832)	(895)	(217)	(3,269)
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings						(2,073)		(2,073)
Impact of adoption of Accounting Standard Update 2016-01					4	775		779
Balance	$ (12,969)	$ (10,616)	$ (10,542)	$ (13,549)	$ (12,007)	$ (11,179)	$ (12,969)	$ (13,549)