Note 3 - Periodic Pension Expense - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Service cost - benefits earned during the period	$ 29	$ 27	$ 87	$ 81
Interest cost on projected benefit obligation	271	242	813	727
Expected return on plan assets	(385)	(429)	(1,106)	(1,288)
Recognized actuarial loss	310	284	959	850
Settlement loss	280		616
Net periodic pension cost	$ 505	$ 124	$ 1,369	$ 370