Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended			12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 01, 2016
Significant Accounting Policies [Line Items]
Computer software developed for internal use into service				$ 11,300,000
Computer software capitalized during period				10,200,000	$ 1,100,000	$ 0
Impairments recognized on assets				0	0	0
Acquisition-related costs				$ 2,616,000	89,000	488,000
More-likely-than-not benefit likelihood percentage being realized upon ultimate settlement with taxing authority resulting from sustainability of tax examination				50.00%
Advertising costs				$ 8,900,000	9,800,000	1,400,000
Reduction to its provision for income taxes	$ 2,214,000	$ 962,000	$ 3,093,000	8,216,000	24,183,000	14,739,000
Cumulative-effect adjustment from adoption of ASU 2016-09				321,000
Long-term deferred income tax assets				69,898,000	65,730,000
Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
Reduction to its provision for income taxes				$ (6,700,000)
Excess tax benefits from operating activities					(5,300,000)	(3,400,000)
Excess tax benefits from financing activities					5,300,000	$ 3,400,000
Long-term deferred income tax assets							$ 321,000
Reclassification Adjustment | Accounting Standards Update 2015-17
Significant Accounting Policies [Line Items]
Long-term deferred income tax assets					12,400,000
Deferred income taxes					$ (12,400,000)
Equipment
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years				3 years
Furniture and fixtures
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years				5 years
Maximum | Capitalized Computer Software
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years				5 years
Maximum | Foreign Exchange Forward
Significant Accounting Policies [Line Items]
Term of derivative contracts				6 months
Minimum | Capitalized Computer Software
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years				3 years
Professional Services Revenues | Maximum
Significant Accounting Policies [Line Items]
Deferred revenue, period of recognition				4 months
Software Licenses | Maximum
Significant Accounting Policies [Line Items]
Term of license agreements				5 years
Software Licenses | Minimum
Significant Accounting Policies [Line Items]
Term of license agreements				3 years
Maintenance
Significant Accounting Policies [Line Items]
Deferred revenue, period of recognition				1 year
Retained Earnings
Significant Accounting Policies [Line Items]
Cumulative-effect adjustment from adoption of ASU 2016-09				$ 321,000
Retained Earnings | Accounting Standards Update 2016-09
Significant Accounting Policies [Line Items]
Cumulative-effect adjustment from adoption of ASU 2016-09							$ 321,000