Segment Reporting - Selected Financial Data for Segments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
External revenue
Service revenue and other	$ 58,132	$ 55,173	$ 54,336	$ 53,134	$ 53,602	$ 51,814	$ 51,551	$ 49,895	$ 220,775	$ 206,862	$ 192,683
Operating expenses
Cost of services									88,203	82,949	80,418
Selling, general and administrative									85,016	77,846	70,844
Depreciation and amortization									48,703	46,786	44,390
Total operating expenses									221,922	207,581	195,652
Operating loss	$ 1,614	$ 470	$ (1,867)	$ (1,364)	$ (550)	$ 681	$ 915	$ (1,765)	(1,147)	(719)	(2,969)
Capital expenditures									120,450	67,048	56,631
Operating Segments | Broadband
External revenue
Service revenue and other									204,347	193,943	183,120
Operating expenses
Selling, general and administrative									39,472	33,545	28,103
Depreciation and amortization									41,076	38,566	35,992
Total operating expenses									163,987	151,346	140,826
Operating loss									40,360	42,597	42,294
Capital expenditures									117,246	60,627	43,197
Operating Segments | Tower
External revenue
Service revenue and other									17,055	12,985	12,196
Operating expenses
Selling, general and administrative									1,430	937	704
Depreciation and amortization									1,906	1,976	2,406
Total operating expenses									8,232	6,690	6,797
Operating loss									8,823	6,295	5,399
Capital expenditures									2,001	921	6,145
Intersegment Eliminations
External revenue
Service revenue and other									18,015	16,346	12,289
Intersegment Eliminations | Broadband
External revenue
Service revenue and other									8,989	10,392	9,906
Intersegment Eliminations | Tower
External revenue
Service revenue and other									9,653	6,020	5,016
Intersegment Eliminations | Corporate & Eliminations
External revenue
Service revenue and other									(627)	(66)	(2,633)
Corporate, Non-Segment
Operating expenses
Selling, general and administrative									44,114	43,364	42,037
Depreciation and amortization									5,721	6,244	5,992
Total operating expenses									49,703	49,545	48,029
Operating loss									(50,330)	(49,611)	(50,662)
Capital expenditures									1,203	5,500	7,289
Residential & SMB | Operating Segments
External revenue
Service revenue and other									154,956	142,290	131,512
Residential & SMB | Operating Segments | Broadband
External revenue
Service revenue and other									154,956	142,290	131,512
Residential & SMB | Operating Segments | Tower
External revenue
Service revenue and other									0	0	0
Commercial Fiber | Operating Segments
External revenue
Service revenue and other									24,431	23,004	22,090
Commercial Fiber | Operating Segments | Broadband
External revenue
Service revenue and other									24,431	23,004	22,090
Commercial Fiber | Operating Segments | Tower
External revenue
Service revenue and other									0	0	0
RLEC & Other | Operating Segments
External revenue
Service revenue and other									15,971	18,257	19,612
RLEC & Other | Operating Segments | Broadband
External revenue
Service revenue and other									15,971	18,257	19,612
RLEC & Other | Operating Segments | Tower
External revenue
Service revenue and other									0	0	0
Tower lease | Operating Segments
External revenue
Service revenue and other									7,402	6,965	7,180
Tower lease | Operating Segments | Broadband
External revenue
Service revenue and other									0	0	0
Tower lease | Operating Segments | Tower
External revenue
Service revenue and other									7,402	6,965	7,180
Service revenue and other | Operating Segments
External revenue
Service revenue and other									202,760	190,516	180,394
Service revenue and other | Operating Segments | Broadband
External revenue
Service revenue and other									195,358	183,551	173,214
Service revenue and other | Operating Segments | Tower
External revenue
Service revenue and other									7,402	6,965	7,180
Cost of services
Operating expenses
Cost of services									88,203	82,949	80,418
Cost of services | Operating Segments | Broadband
Operating expenses
Cost of services									83,439	79,235	76,731
Cost of services | Operating Segments | Tower
Operating expenses
Cost of services									4,896	3,777	3,687
Cost of services | Corporate, Non-Segment
Operating expenses
Cost of services									$ (132)	$ (63)	$ 0