Long-Lived Assets - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Depreciation, amortization and accretion expense		$ 13,970,000	$ 16,677,000	$ 15,167,000
Depreciation		8,570,000	10,200,000	9,664,000
Change in accounting estimate will reduce depreciation expense	$ 36,000
Other long-term liabilities	8,972,000	$ 8,972,000	8,131,000
Percentage of fair value estimate of contractor fees escalation by each year		4.00%
Long term cost associated with estimated removal costs		$ 9,300,000
Accretion expense on the asset retirement obligation liabilities		665,000	755,000
Impairment charge of intangible assets		0	0	0
Goodwill	133,031,000	133,031,000	133,031,000
Goodwill impairment loss		0	0	0
Paging and computer equipment
Finite-Lived Intangible Assets [Line Items]
Depreciation		700,000	900,000	1,100,000
Paging Equipment Assets
Finite-Lived Intangible Assets [Line Items]
Depreciation, amortization and accretion expense		500,000	300,000	1,000,000
Asset retirement costs	3,600,000	3,600,000	2,800,000
Asset retirement obligation liability
Finite-Lived Intangible Assets [Line Items]
Accrued other liabilities	300,000	300,000	300,000
Costs of deconstructing assets
Finite-Lived Intangible Assets [Line Items]
Other long-term liabilities	$ 7,500,000	7,500,000	6,800,000
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Accretion expense on the asset retirement obligation liabilities		700,000	800,000	500,000
Amortization expense for other intangible assets		$ 4,700,000	5,700,000	$ 5,000,000
Software Operations
Finite-Lived Intangible Assets [Line Items]
Period already amortized		3 years
Remaining amortization period		3 years
Minimum | Paging Equipment Assets
Finite-Lived Intangible Assets [Line Items]
Equipment assets estimated useful life		1 year
Minimum | Software Operations
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)		2 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)		15 years
Maximum | Paging Equipment Assets
Finite-Lived Intangible Assets [Line Items]
Equipment assets estimated useful life		5 years
Maximum | Software Operations
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)		15 years
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Increase (decrease) in intangible assets, current		$ 0	$ 52,000
Non-compete agreements | Wireless Operations
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)		3 years
Non-compete agreements | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)		3 years
Non-compete agreements | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)		5 years