Revenue from Contracts with Customers - Revenue by Category (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ (158,843)	$ (154,138)
Wireless
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(114,384)	(111,565)
Cable
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(32,240)	(30,680)
Wireline
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(12,219)	(11,893)
Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(168,272)	(164,222)
Operating Segments | Wireless service
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(97,075)	(92,165)
Operating Segments | Equipment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(15,612)	(17,579)
Operating Segments | Business, residential and enterprise
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(41,080)	(39,822)
Operating Segments | Tower and other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(14,505)	(14,656)
Operating Segments | Wireless
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(115,654)	(112,804)
Operating Segments | Wireless | Wireless service
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(97,075)	(92,165)
Operating Segments | Wireless | Equipment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(15,291)	(17,374)
Operating Segments | Wireless | Business, residential and enterprise
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating Segments | Wireless | Tower and other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(3,288)	(3,265)
Operating Segments | Cable
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(33,709)	(31,711)
Operating Segments | Cable | Wireless service
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating Segments | Cable | Equipment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(270)	(159)
Operating Segments | Cable | Business, residential and enterprise
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(30,518)	(29,131)
Operating Segments | Cable | Tower and other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(2,921)	(2,421)
Operating Segments | Wireline
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(18,909)	(19,707)
Operating Segments | Wireline | Wireless service
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating Segments | Wireline | Equipment
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(51)	(46)
Operating Segments | Wireline | Business, residential and enterprise
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(10,562)	(10,691)
Operating Segments | Wireline | Tower and other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(8,296)	(8,970)
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	9,429	10,084
Intersegment Eliminations | Wireless
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,270	1,239
Intersegment Eliminations | Cable
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,469	1,031
Intersegment Eliminations | Wireline
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 6,690	$ 7,814