Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Allowance for loan losses	$ 3,285	$ 3,625
Deferred directors’ fees	236	242
Postretirement benefit obligations	5,825	5,665
Other real estate owned	1,303	1,968
Self-funded insurance	232	230
Paid time off	815	756
Depreciation	1,630	1,440
Intangibles	1,878	2,432
Unrealized loss on available for sale investment securities, net	1,811
Other	239	307
Total deferred tax assets	17,254	16,665
Unrealized gains on available for sale investment securities, net		1,734
Prepaid expenses	153	306
Federal Home Loan Bank stock dividends	1,035	1,035
Deferred loan fees	846	806
Other	52	65
Total deferred tax liabilities	2,086	3,946
Net deferred tax asset	$ 15,168	$ 12,719