Segment Reporting - Selected Financial Data for Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
External revenues [Abstract]
Operating revenues	$ 154,030	$ 153,258	$ 305,762	$ 307,138
Revenue, Net	154,030	153,258	305,762	307,138
Operating expenses:
Cost of services	(49,134)	(48,416)	(98,476)	(97,193)
Cost of goods sold	15,166	4,965	30,971	9,949
Selling, general and administrative	(29,915)	(43,022)	(58,665)	(83,175)
Acquisition, integration and migration expenses	0	(3,678)	0	(8,167)
Depreciation amortization	(41,117)	(44,925)	(84,604)	(89,729)
Total operating expenses	135,332	145,006	272,716	288,213
Operating income (loss)	18,698	8,252	33,046	18,925
Wireless
External revenues [Abstract]
Operating revenues	111,038	112,899	220,197	227,128
Cable
External revenues [Abstract]
Operating revenues	31,014	28,978	61,694	57,423
Wireline
External revenues [Abstract]
Operating revenues	11,978	11,381	23,871	22,587
Other
External revenues [Abstract]
Operating revenues	0	0	0	0
Operating Segments
External revenues [Abstract]
Operating revenues	163,505		325,321
Operating Segments | Wireless
External revenues [Abstract]
Operating revenues	112,282		222,680
Revenue, Net	112,282	114,133	222,680	229,596
Operating expenses:
Cost of services	(33,488)	(33,497)	(67,238)	(66,920)
Cost of goods sold	15,082	4,972	30,809	9,868
Selling, general and administrative	(12,367)	(29,637)	(24,502)	(58,101)
Acquisition, integration and migration expenses		(4,124)		(7,916)
Depreciation amortization	(31,565)	(35,551)	(65,490)	(71,303)
Total operating expenses	92,502	107,781	188,039	214,108
Operating income (loss)	19,780	6,352	34,641	15,488
Operating Segments | Cable
External revenues [Abstract]
Operating revenues	32,111		63,822
Revenue, Net	32,111	29,564	63,822	58,577
Operating expenses:
Cost of services	(15,125)	(14,920)	(30,281)	(30,098)
Cost of goods sold	63	(9)	119	41
Selling, general and administrative	(4,661)	(4,867)	(9,609)	(9,725)
Acquisition, integration and migration expenses		0		0
Depreciation amortization	(6,179)	(6,090)	(12,203)	(11,879)
Total operating expenses	26,028	25,868	52,212	51,743
Operating income (loss)	6,083	3,696	11,610	6,834
Operating Segments | Wireline
External revenues [Abstract]
Operating revenues	19,112		38,819
Revenue, Net	19,112	19,576	38,819	38,730
Operating expenses:
Cost of services	(9,373)	(9,329)	(19,175)	(18,563)
Cost of goods sold	20	1	42	40
Selling, general and administrative	(1,686)	(1,683)	(3,403)	(3,359)
Acquisition, integration and migration expenses		0		0
Depreciation amortization	(3,240)	(3,155)	(6,634)	(6,286)
Total operating expenses	14,319	14,168	29,254	28,248
Operating income (loss)	4,793	5,408	9,565	10,482
Operating Segments | Other
External revenues [Abstract]
Revenue, Net	0	0	0	0
Operating expenses:
Cost of services	(12)	0	(12)	0
Cost of goods sold	1	0	1	0
Selling, general and administrative	(11,812)	(7,521)	(22,480)	(13,367)
Acquisition, integration and migration expenses		446		(251)
Depreciation amortization	(133)	(129)	(277)	(261)
Total operating expenses	11,958	7,204	22,770	13,879
Operating income (loss)	(11,958)	(7,204)	(22,770)	(13,879)
Intersegment Eliminations
External revenues [Abstract]
Operating revenues	(9,475)		(19,559)
Revenue, Net	(9,475)	(10,015)	(19,559)	(19,765)
Operating expenses:
Cost of services	8,864	9,329	18,230	18,388
Cost of goods sold	0	0	0	0
Selling, general and administrative	611	686	1,329	1,377
Acquisition, integration and migration expenses		0		0
Depreciation amortization	0	0	0	0
Total operating expenses	(9,475)	(10,015)	(19,559)	(19,765)
Operating income (loss)	0	0	0	0
Intersegment Eliminations | Wireless
External revenues [Abstract]
Operating revenues	(1,244)		(2,483)
Revenue, Net	1,244	1,234	2,483	2,468
Intersegment Eliminations | Cable
External revenues [Abstract]
Operating revenues	(1,097)		(2,128)
Revenue, Net	1,097	586	2,128	1,154
Intersegment Eliminations | Wireline
External revenues [Abstract]
Operating revenues	(7,134)		(14,948)
Revenue, Net	7,134	8,195	14,948	16,143
Intersegment Eliminations | Other
External revenues [Abstract]
Revenue, Net	0	0	0	0
Service revenues
External revenues [Abstract]
Operating revenues	127,268	139,692	250,806	279,337
Service revenues | Wireless
External revenues [Abstract]
Operating revenues	93,219	107,681	182,978	215,867
Service revenues | Cable
External revenues [Abstract]
Operating revenues	28,748	26,883	57,219	53,294
Service revenues | Wireline
External revenues [Abstract]
Operating revenues	5,301	5,128	10,609	10,176
Service revenues | Other
External revenues [Abstract]
Operating revenues	0	0	0	0
Equipment revenues
External revenues [Abstract]
Operating revenues	16,009	2,950	33,588	6,309
Equipment revenues | Wireless
External revenues [Abstract]
Operating revenues	15,819	2,779	33,193	5,924
Equipment revenues | Cable
External revenues [Abstract]
Operating revenues	144	147	303	329
Equipment revenues | Wireline
External revenues [Abstract]
Operating revenues	46	24	92	56
Equipment revenues | Other
External revenues [Abstract]
Operating revenues	0	0	0	0
Other
External revenues [Abstract]
Operating revenues	10,753	10,616	21,368	21,492
Other | Wireless
External revenues [Abstract]
Operating revenues	2,000	2,439	4,026	5,337
Other | Cable
External revenues [Abstract]
Operating revenues	2,122	1,948	4,172	3,800
Other | Wireline
External revenues [Abstract]
Operating revenues	6,631	6,229	13,170	12,355
Other | Other
External revenues [Abstract]
Operating revenues	$ 0	$ 0	$ 0	$ 0