Segment and Related Information - Reconciliation of Operating Income from Segments to Consolidated (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information
Total segment operating income	$ 41,341	$ 36,666	$ 75,234	$ 71,157
Other income (expense), net	470	(247)	1,460	339
Income before income taxes	41,811	36,419	76,694	71,496
Operating segment and corporate non-segment
Segment Reporting Information
Total segment operating income	54,739	49,920	102,051	95,943
Segment reconciling items
Segment Reporting Information
Other income (expense), net	470	(247)	1,460	339
Segment reconciling items | Acquired software
Segment Reporting Information
Amortization of intangibles assets	(8,006)	(7,988)	(16,033)	(14,670)
Segment reconciling items | Customer and trade name
Segment Reporting Information
Amortization of intangibles assets	$ (5,392)	$ (5,266)	$ (10,784)	$ (10,116)