Note 14 - Retirement Plans - Schedule of Measuring Fair Value of Plan Assets Regarding ACS Retirement Plan (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	$ 11,435
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	9,997
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1,438
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Money Market Funds [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	38
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	38
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance
International Growth [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,215	[1]
International Growth [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,215	[1]
International Growth [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
International Growth [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
U.S Small Cap [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1,341	[1]
U.S Small Cap [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1,341	[1]
U.S Small Cap [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
U.S Small Cap [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
U.S. Medium Cap [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	692	[1]
U.S. Medium Cap [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	692	[1]
U.S. Medium Cap [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
U.S. Medium Cap [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
U.S. Large Cap [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	3,338	[1]
U.S. Large Cap [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	3,338	[1]
U.S. Large Cap [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
U.S. Large Cap [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
Certificates of Deposit [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,411	[1]
Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	2,411	[1]
Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
Certificates of Deposit [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
Fixed Income Securities [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1,400	[1]
Fixed Income Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]
Fixed Income Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance	1,400	[1]
Fixed Income Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Plan Assets, Amount, Ending Balance		[1]

[1] May include mutual funds comprised of both stocks and bonds.