Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($) Segment ClassOfCommonStock $ / shares	Dec. 31, 2016 ClassOfCommonStock
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments \| Segment		3
Number of class of common stock outstanding \| ClassOfCommonStock		1	1
Increases in depreciation expense	$ 8.6	$ 14.9
Decrease in cost of service revenue	$ (1.3)	$ (3.5)
Increase in net loss per basic and fully diluted share \| $ / shares	$ 0.09	$ 0.14

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

No definition available.

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Period Type:	duration