Note 3 - Revenues - Revenues by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues	$ 284,991	$ 268,268	$ 849,246	$ 802,443
Data [Member]
Revenues	134,320	124,089	396,955	366,418
Video [Member]
Revenues	80,999	84,583	248,834	260,807
Voice [Member]
Revenues	10,254	10,169	30,584	31,345
Business Services [Member]
Revenues	50,662	39,567	147,564	115,739
Advertising [Member]
Revenues	5,054	6,288	14,534	17,445
Product and Service, Other [Member]
Revenues	$ 3,702	$ 3,572	$ 10,775	$ 10,689