Recent Accounting Standards - Line Items Adjusted in Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounts receivable, net	$ 125,115	$ 165,364
Prepaid expenses and other current assets	27,863	19,180
Deposits and other assets	7,112	7,411
Deferred tax assets, net	14,761	9,297
Deferred revenue and advance payments	175,358	198,734
Deferred revenue and advance payments, non-current	5,816	6,400
Accumulated other comprehensive loss	(8,111)	(5,659)
Retained earnings	$ 533,134	526,633
As Reported
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounts receivable, net		69,500
Prepaid expenses and other current assets		18,002
Deposits and other assets		2,868
Deferred tax assets, net		13,391
Deferred revenue and advance payments		112,649
Deferred revenue and advance payments, non-current		10,181
Accumulated other comprehensive loss		(5,968)
Retained earnings		511,755
Effect of the Adoption | ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounts receivable, net		95,864
Prepaid expenses and other current assets		1,178
Deposits and other assets		4,543
Deferred tax assets, net		(4,094)
Deferred revenue and advance payments		86,085
Deferred revenue and advance payments, non-current		(3,781)
Accumulated other comprehensive loss		309
Retained earnings		$ 14,878