Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Schedule of Accrued Liabilities [Line Items]
Outside professional services		$ 11,638	$ 14,468
Income and other taxes		3,971	7,420
Marketing and sales program expenses		4,623	6,444
Dividends payable		2,365	2,344
Employee-related expenses		5,212	4,065
Other		12,020	10,767
Total accrued expenses	[1]	$ 39,829	$ 45,508

[1] On January 1, 2018, the Company adopted the ASC 606 revenue recognition standard and has adjusted prior periods to conform. See Note 2. "New Accounting Pronouncements" for additional information.