Note 14 - Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Balance	$ 549,464	$ 532,608
Net current period other comprehensive income (loss), net of tax	2,210	(895)
Balance	559,559	535,307
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance	(15,649)	(5,522)
Other comprehensive income before reclassifications, net of tax	5,620	(6,640)
Amounts reclassified from accumulated other comprehensive income, net of tax
Net current period other comprehensive income (loss), net of tax	5,620	(6,640)
Balance	(10,029)	(13,487)
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
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Balance	3,704	231
Other comprehensive income before reclassifications, net of tax	(3,644)	5,481
Amounts reclassified from accumulated other comprehensive income, net of tax	139	180
Net current period other comprehensive income (loss), net of tax	(3,505)	5,661
Balance	199	5,942
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
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(1,673)	(3,695)
Other comprehensive income before reclassifications, net of tax
Amounts reclassified from accumulated other comprehensive income, net of tax	7	84
Net current period other comprehensive income (loss), net of tax	7	84
Balance	(1,666)	(4,409)
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
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Balance	866
Other comprehensive income before reclassifications, net of tax	88
Amounts reclassified from accumulated other comprehensive income, net of tax
Net current period other comprehensive income (loss), net of tax	88
Balance	954	775
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings
Impact of adoption of Accounting Standard Update 2016-01		775
AOCI Attributable to Parent [Member]
Balance	(12,752)	(8,986)
Other comprehensive income before reclassifications, net of tax	2,064	(1,159)
Amounts reclassified from accumulated other comprehensive income, net of tax	146	264
Net current period other comprehensive income (loss), net of tax	2,210	(895)
Balance	$ (10,542)	(11,179)
Reclassification of the Income tax effects of Tax Cuts and Jobs Act from AOCI to Retained Earnings		(2,073)
Impact of adoption of Accounting Standard Update 2016-01		$ 775