Note 14 - Retirement Plans - Summary of Net Periodic Pension Expense for ACS Retirement Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest cost	$ 117	$ 153	$ 351	$ 453
Expected return on plan assets	(185)	(169)	(556)	(508)
Amortization of loss	36	(176)	107	106
Net periodic pension expense	$ (32)	$ (192)	$ (98)	$ 51