Note 3 - Periodic Pension Expense - Net Periodic Benefit Cost (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Service cost - benefits earned during the period	$ 16,000	$ 14,000	$ 32,000	$ 28,000
Interest cost on projected benefit obligation	242,000	247,000	483,000	494,000
Expected return on plan assets	(305,000)	(297,000)	(609,000)	(594,000)
Recognized actuarial loss	270,000	258,000	547,000	523,000
Settlement loss	277,000	52,000	277,000	307,000
Net periodic pension cost	$ 500,000	$ 274,000	$ 730,000	$ 758,000