Segment Information - Selected Financial Data for Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
External revenues [Abstract]
Service revenues	$ 139,455	$ 140,897	$ 418,792	$ 338,235
Other	12,327	15,939	40,128	41,481
Total operating revenues	151,782	156,836	458,920	379,716
Operating expenses:
Costs of goods and services, exclusive of depreciation and amortization shown separately below	55,834	58,317	162,976	140,354
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	42,199	40,369	125,374	96,263
Integration and acquisition expenses	1,706	15,272	9,873	35,801
Depreciation and amortization	42,568	46,807	132,297	96,961
Total operating expenses	142,307	160,765	430,520	369,379
Operating income (loss)	9,475	(3,929)	28,400	10,337
Wireless
External revenues [Abstract]
Service revenues	107,395	111,001	323,262	250,053
Other	3,871	7,978	15,133	17,461
Total operating revenues	111,266	118,979	338,395	267,514
Cable
External revenues [Abstract]
Service revenues	26,934	24,948	80,229	73,455
Other	2,156	2,031	6,283	5,799
Total operating revenues	29,090	26,979	86,512	79,254
Wireline
External revenues [Abstract]
Service revenues	5,126	4,948	15,301	14,727
Other	6,300	5,930	18,712	18,221
Total operating revenues	11,426	10,878	34,013	32,948
Other
External revenues [Abstract]
Service revenues	0	0	0	0
Other	0	0	0	0
Total operating revenues	0	0	0	0
Operating Segments | Wireless
External revenues [Abstract]
Total operating revenues	112,505	120,119	342,102	270,931
Operating expenses:
Costs of goods and services, exclusive of depreciation and amortization shown separately below	41,041	43,097	117,829	94,892
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	30,099	29,892	88,201	65,219
Integration and acquisition expenses	1,691	14,499	9,607	19,889
Depreciation and amortization	32,929	38,038	104,231	70,026
Total operating expenses	105,760	125,526	319,868	250,026
Operating income (loss)	6,745	(5,407)	22,234	20,905
Operating Segments | Cable
External revenues [Abstract]
Total operating revenues	30,089	27,566	88,665	80,413
Operating expenses:
Costs of goods and services, exclusive of depreciation and amortization shown separately below	14,913	14,654	45,052	43,864
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	5,358	4,770	15,083	14,672
Integration and acquisition expenses	0	0	0	0
Depreciation and amortization	6,192	5,860	18,070	17,834
Total operating expenses	26,463	25,284	78,205	76,370
Operating income (loss)	3,626	2,282	10,460	4,043
Operating Segments | Wireline
External revenues [Abstract]
Total operating revenues	19,851	18,732	58,581	55,702
Operating expenses:
Costs of goods and services, exclusive of depreciation and amortization shown separately below	9,807	9,442	28,409	26,892
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	1,706	1,676	5,065	4,951
Integration and acquisition expenses	0	0	0	0
Depreciation and amortization	3,249	2,822	9,536	8,789
Total operating expenses	14,762	13,940	43,010	40,632
Operating income (loss)	5,089	4,792	15,571	15,070
Operating Segments | Other
External revenues [Abstract]
Total operating revenues	0	0	0	0
Operating expenses:
Costs of goods and services, exclusive of depreciation and amortization shown separately below	0	0	0	0
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	5,772	4,736	19,139	13,457
Integration and acquisition expenses	15	800	266	15,900
Depreciation and amortization	198	87	460	312
Total operating expenses	5,985	5,596	19,865	29,681
Operating income (loss)	(5,985)	(5,596)	(19,865)	(29,681)
Intersegment Eliminations
External revenues [Abstract]
Total operating revenues	(10,663)	(9,581)	(30,428)	(27,330)
Operating expenses:
Costs of goods and services, exclusive of depreciation and amortization shown separately below	(9,927)	(8,876)	(28,314)	(25,294)
Selling, general and administrative, exclusive of depreciation and amortization shown separately below	(736)	(705)	(2,114)	(2,036)
Integration and acquisition expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Total operating expenses	(10,663)	(9,581)	(30,428)	(27,330)
Operating income (loss)	0	0	0	0
Intersegment Eliminations | Wireless
External revenues [Abstract]
Total operating revenues	1,239	1,140	3,707	3,417
Intersegment Eliminations | Cable
External revenues [Abstract]
Total operating revenues	999	587	2,153	1,159
Intersegment Eliminations | Wireline
External revenues [Abstract]
Total operating revenues	8,425	7,854	$ 24,568	22,754
Intersegment Eliminations | Other
External revenues [Abstract]
Total operating revenues	$ 0	$ 0		$ 0