Note 1 - Description of Company and Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019	Jan. 08, 2018
Restricted Cash and Cash Equivalents, Current, Total	$ 1,631,000	$ 1,634,000
Equipment and Buildings Under Capital Leases, Expiration Period	2033
Preferred Stock, Shares Authorized	5,000			145
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred Stock, Shares Issued, Total	0	0		0
Preferred Stock, Shares Outstanding, Ending Balance	0	0
Advertising Expense	$ 2,829,000	$ 3,074,000
Operating Lease, Right-of-Use Asset	$ 80,991,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total			$ 82,020,000
Operating Lease, Right-of-Use Asset			$ 82,020,000
Workforce Subject to Collective Bargaining Arrangements [Member] | Unionized Employees Concentration Risk [Member] | IBEW [Member]
Concentration Risk, Percentage	54.00%
Revenue Benchmark [Member] | Product Concentration Risk [Member] | High Cost Support [Member]
Concentration Risk, Percentage	9.00%
Revenue Benchmark [Member] | Product Concentration Risk [Member] | Rural Health Care Universal Service Support [Member]
Concentration Risk, Percentage	6.00%
The 2017 Share Repurchase Program [Member]
Stock Repurchase Program, Authorized Amount	$ 10,000,000
Treasury Stock, Shares, Acquired	1,000
Treasury Stock Acquired, Average Cost Per Share	$ 1.81
Treasury Stock, Value, Acquired, Cost Method	$ 1,812
Chief Executive Officer [Member]
Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits	1,715,000
Payments for Postemployment Benefits	$ 1,390,000
Minimum [Member]
Property, Plant and Equipment, Useful Life	5 years
Employee Stock Purchase Plan, Payroll Deduction Per Employee, Percent	1.00%
Maximum [Member]
Property, Plant and Equipment, Useful Life	50 years
Employee Stock Purchase Plan, Payroll Deduction Per Employee, Percent	15.00%
Certificates of Deposit [Member]
Restricted Cash and Cash Equivalents, Current, Total	$ 1,600,000
Other Restricted Cash [Member]
Restricted Cash and Cash Equivalents, Current, Total	$ 31,000
Noncontrolling Interest [Member] | Quintillion Holdings, LLC [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	50.00%
ACS Cable Systems LLC and Quintillion Holdings, LLC Joint Venture [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	50.00%