Recent Accounting Pronouncements - Summary of Adjustments to Accounts on Condensed Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017
Recent Accounting Pronouncements [Line Items]
Net loss		$ (16,792)	$ (36,833)	$ (60,941)		$ (53,123)
Deferred income taxes				(29,681)		(22,770)
Changes in operating assets and liabilities:
Accounts receivable, net				(77,416)		$ (16,834)
Net cash used in operating activities				(76,366)
Adjustments
Recent Accounting Pronouncements [Line Items]
Net loss	[1]	37		(20,925)	[2]
Deferred income taxes	[2]			(6,225)
Changes in operating assets and liabilities:
Accounts receivable, net	[2]			27,150
Net cash used in operating activities	[2]			0
Balance Without Adoption of ASC 606
Recent Accounting Pronouncements [Line Items]
Net loss		$ (16,755)		(81,866)
Deferred income taxes				(35,906)
Changes in operating assets and liabilities:
Accounts receivable, net				(50,266)
Net cash used in operating activities				$ (76,366)

[1] The adoption of ASC 606 resulted in additional revenues recognized in the first half of 2018, which in turn generated additional deferred tax liabilities that reduced the Company's benefit from income taxes. The Benefit from Income Taxes amount has been calculated using the Company’s estimated statutory rate.

[2] The adoption of ASC 606 resulted in decreased Net Loss and increased Accounts Receivable, Net due to additional revenues recognized in the first quarter of 2018, which in turn generated additional deferred tax liabilities that reduced the Company's net Deferred Tax Assets. The Deferred Income Taxes amount has been calculated using the Company’s estimated statutory rate.