Note 3 - Periodic Pension Expense - Net Periodic Benefit Cost (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Service cost - benefits earned during the period	$ 17,000	$ 15,000	$ 49,000	$ 43,000
Interest cost on projected benefit obligation	241,000	247,000	724,000	741,000
Expected return on plan assets	(305,000)	(297,000)	(914,000)	(891,000)
Recognized actuarial loss	253,000	253,000	800,000	776,000
Settlement loss	158,000	94,000	435,000	401,000
Net periodic pension cost	$ 364,000	$ 312,000	$ 1,094,000	$ 1,070,000