Note 14 - Retirement Plans - Funded Status of ACS Retirement Plan Using Beginning and Ending Balances for Projected Benefit Obligation and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest cost	$ 604	$ 566
Fair value of plan assets at end of year	11,435
401K [Member]
Benefit obligation at beginning of year	14,499	15,798
Interest cost	604	566
Actuarial loss (gain)	1,221	(872)
Benefits paid	(1,166)	(993)
Benefit obligation at end of year	15,158	14,499
Fair value of plan assets at beginning of year	10,871	12,534
Actual return (loss) on plan assets	1,662	(863)
Employer contribution	81	192
Benefits paid	(1,166)	(992)
Fair value of plan assets at end of year	11,448	10,871
Funded status	$ (3,710)	$ (3,628)