Note 7 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands			12 Months Ended
	Feb. 02, 2015	Dec. 04, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 14, 2017	Mar. 31, 2017	Mar. 28, 2017	Mar. 17, 2017	Nov. 27, 2015	Apr. 02, 2015	Dec. 31, 2014
Derivative Notional Amount of Fixed Interest Rate Swaps Over Hedged, Percentage	95.50%
Derivative Notional Amount of Fixed Interest Rate Swaps Over Hedged	$ 110,268
Derivative, Gain (Loss) on Derivative, Net					$ 820
Deferred Capacity Revenue, Fair Value	$ 41,287
Service Obligation, Carrying Amount			$ 35,255	$ 37,326
Indefeasible Right of Use Assets, Fair Value Disclosure											$ 2,304
Indefeasible Right of Use Obligations, Fair Value Disclosure											$ 4,153
Impairment of Long-Lived Assets to be Disposed of			$ 0	$ 0	$ 0
Minimum [Member]
Deferred Revenues, Amortization Period	10 years
Maximum [Member]
Deferred Revenues, Amortization Period	30 years
Interest Rate Swap Redesignated from 2015 Senior Credit Facilities to 2017 Senior Credit Facilities [Member]
Derivative, Notional Amount							$ 42,058
Derivative, Fixed Interest Rate			6.333%
Interest Rate Swap Redesignated from 2015 Senior Credit Facilities to 2017 Senior Credit Facilities [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative, Basis Spread on Variable Rate			5.00%
Interest Rate Swap [Member]
Derivative, Notional Amount						$ 48,635				$ 44,827
Derivative, Fixed Interest Rate						6.49425%				5.833%
Derivative Final Notional Amount						$ 90,000
Interest Rate Swap [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative, Basis Spread on Variable Rate						5.00%				4.50%
Interest Rate Swap, One [Member]
Derivative, Notional Amount												$ 115,500
Derivative, Fixed Interest Rate												7.22%
Interest Rate Swap, One [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative, Basis Spread on Variable Rate												4.75%
Interest Rate Swap, Two [Member]
Derivative, Notional Amount												$ 77,000
Derivative, Fixed Interest Rate												7.225%
Interest Rate Swap, Two [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative, Basis Spread on Variable Rate												4.75%
6.25% Convertible Notes Due 2018 [Member]
Debt Instrument, Interest Rate, Stated Percentage			6.25%	6.25%				6.25%	6.25%
Debt and Capital Lease Obligations			$ 10,026
6.25% Convertible Notes Due 2018 [Member] | Fair Value, Inputs, Level 2 [Member]
Debt and Capital Lease Obligations, Fair Value Disclosures			10,026
Senior Credit Facilities and Other Long-Term Obligations [Member]
Debt and Capital Lease Obligations			178,836
The 2017 Senior Credit Facility [Member]
Debt Instrument Covenants, Minimum Borrowing			$ 90,000
Weighted Average Life of Senior Credit Facility			2 years
2010 Senior Credit Facility [Member]
Anticipated Debt Paid from Wireless Sale		$ 240,472