Note 15 - Income Taxes - Significant Components of Company's Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carry forwards	$ 19,805	$ 26,429
Deferred GCI capacity revenue	10,016	15,340
Reserves and accruals	7,910	12,499
Intangibles and goodwill	1,033	1,620
Fair value on interest rate swaps		25
Pension liability	927	1,804
Allowance for doubtful accounts	775	458
Alternative minimum tax carry forward		9,380
Other		257
Total deferred tax assets	40,466	67,812
Valuation allowance	(204)	(139)
Deferred tax assets after valuation allowance	40,262	67,673
Deferred tax liabilities:
Debt issuance costs	(5)	(933)
Property, plant and equipment	(37,287)	(52,022)
Fair value on interest rate swaps	(146)
Other	(26)
Total deferred tax liabilities	(37,464)	(52,955)
Net deferred tax asset	$ 2,798	$ 14,718