Note 20 - Revenue From Contracts With Customers - Revenue by Operating Segment (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2018		Sep. 30, 2017
Mortgage banking	[1]	$ 712		$ 781		$ 2,034		$ 2,380
Bank owned life insurance	[1]	186		204		564		964
Total non-interest income		11,426		10,945		33,770		33,092
Gain on callsale of securities available for sale (1)				31				31
Commercial Banking [Member]
Mortgage banking	[1]	712		781		2,034		2,380
Bank owned life insurance	[1]	186		204		564		964
Total non-interest income		6,046		5,920		17,546		17,820
Gain on callsale of securities available for sale (1)				31				31
Investment Management and Trust [Member]
Mortgage banking	[1]
Bank owned life insurance	[1]
Total non-interest income		5,380		5,025		16,224		15,272
Gain on callsale of securities available for sale (1)
Fiduciary and Trust [Member]
Non-interest income		5,380		5,025		16,224		15,272
Fiduciary and Trust [Member] | Commercial Banking [Member]
Non-interest income
Fiduciary and Trust [Member] | Investment Management and Trust [Member]
Non-interest income		5,380		5,025		16,224		15,272
Deposit Account [Member]
Non-interest income		1,482		1,568		4,340		4,583
Deposit Account [Member] | Commercial Banking [Member]
Non-interest income		1,482		1,568		4,340		4,583
Deposit Account [Member] | Investment Management and Trust [Member]
Non-interest income
Credit and Debit Card [Member]
Non-interest income		1,759		1,492		4,956		4,412
Credit and Debit Card [Member] | Commercial Banking [Member]
Non-interest income		1,759		1,492		4,956		4,412
Credit and Debit Card [Member] | Investment Management and Trust [Member]
Non-interest income
Treasury Management [Member]
Non-interest income		1,151		1,083		3,311		3,187
Treasury Management [Member] | Commercial Banking [Member]
Non-interest income		1,151		1,083		3,311		3,187
Treasury Management [Member] | Investment Management and Trust [Member]
Non-interest income
Investment Advisory, Management and Administrative Service [Member]
Non-interest income		444		404		1,245		1,147
Investment Advisory, Management and Administrative Service [Member] | Commercial Banking [Member]
Non-interest income		444		404		1,245		1,147
Investment Advisory, Management and Administrative Service [Member] | Investment Management and Trust [Member]
Non-interest income
Product and Service, Other [Member]
Non-interest income		312	[2]	357	[3]	1,096	[2]	1,116	[3]
Product and Service, Other [Member] | Commercial Banking [Member]
Non-interest income		312	[2]	357	[3]	1,096	[2]	1,116	[3]
Product and Service, Other [Member] | Investment Management and Trust [Member]
Non-interest income			[2]		[3]		[2]		[3]

[1] Not within the scope of ASC 606

[2] Includes safe box deposit fees of $46,000 quarterly and $137,000 year-to-date included within the scope of ASC 606

[3] Includes safe box deposit fees of $43,000 quarterly and $128,000 year-to-date included within the scope of ASC 606