Note 10 - Income Taxes (Details) - Income Tax Expense - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Expense [Abstract]
Currently payable									$ 3,662	$ 2,168	$ 4,908
Deferred									1,631	3,931	(473)
Total applicable to operations	$ 1,080	$ 1,439	$ 1,369	$ 1,405	$ 1,737	$ 1,283	$ 1,959	$ 1,120	5,293	6,099	4,435
Deferred tax (credited) charged to components of shareholders’ equity:
Unfunded status of postretirement benefits									(74)	(382)	1,589
Net unrealized securities (losses) gains									(1,052)	4,737	(7,019)
Total income taxes									$ 4,167	$ 10,454	$ (995)