Consolidated Financial Statement Components - Depreciation, Amortization and Accretion (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Depreciation	$ 2,024	$ 2,009	$ 5,887	$ 6,167
Amortization	625	625	1,875	2,261
Accretion	136	141	406	421
Total depreciation, amortization and accretion expense	2,785	2,775	8,168	8,849
Leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciation	60	50	195	175
Asset retirement costs
Property, Plant and Equipment [Line Items]
Depreciation	(74)	(97)	(226)	(292)
Paging and computer equipment
Property, Plant and Equipment [Line Items]
Depreciation	1,938	1,990	5,608	6,077
Furniture, fixtures and vehicles
Property, Plant and Equipment [Line Items]
Depreciation	$ 100	$ 66	$ 310	$ 207

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

+ References

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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