Note 14 - Retirement Plans - Summary of Net Periodic Pension Expense for ACS Retirement Plan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest cost	$ 150	$ 141
Expected return on plan assets	(170)	(198)
Amortization of loss	141	148
Net periodic pension expense	$ 121	$ 91