Acquisitions - Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Feb. 01, 2019
Business Acquisition [Line Items]
Cash	$ 16,486
Accounts receivable and other tangible assets	15,676
Accounts payable and other liabilities	(11,107)
Deferred revenue	(3,266)
Net deferred tax liabilities	(14,871)
Total identifiable net assets	93,280
Goodwill	218,193
Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets	50,206
Customer Lists and Contract Backlog
Business Acquisition [Line Items]
Finite-lived intangible assets	34,196
Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets	5,960
Granta Design
Business Acquisition [Line Items]
Cash		$ 13,644
Accounts receivable and other tangible assets		7,023
Accounts payable and other liabilities		(6,403)
Deferred revenue		(1,426)
Net deferred tax liabilities		(9,822)
Total identifiable net assets		60,056
Goodwill		148,680
Granta Design | Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets		32,445
Granta Design | Customer Lists and Contract Backlog
Business Acquisition [Line Items]
Finite-lived intangible assets		20,016
Granta Design | Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets		$ 4,579
Other Acquisitions
Business Acquisition [Line Items]
Cash	2,842
Accounts receivable and other tangible assets	8,653
Accounts payable and other liabilities	(4,704)
Deferred revenue	(1,840)
Net deferred tax liabilities	(5,049)
Total identifiable net assets	33,224
Goodwill	69,513
Other Acquisitions | Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets	17,761
Other Acquisitions | Customer Lists and Contract Backlog
Business Acquisition [Line Items]
Finite-lived intangible assets	14,180
Other Acquisitions | Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets	$ 1,381