Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended	6 Months Ended
	Jan. 02, 2018	Mar. 31, 2017	Apr. 30, 2018	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2017
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired				$ 44,176	$ 805,218
Goodwill			$ 1,616,800	1,616,800		$ 1,589,210
Term loan facility			1,539,046	1,539,046
Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Goodwill			$ 1,196,176	$ 1,196,176		$ 1,172,857
Sonoscan, Inc. [Member] | 2018 Acquisition [Member]
Business Acquisition [Line Items]
Acquired percent of the outstanding shares	100.00%
Acquisition of businesses, net of cash acquired	$ 44,832
Cash acquired from business acquisition	656
Goodwill	21,363
Identifiable intangible assets	7,910
Sonoscan, Inc. [Member] | Customer Relationships [Member] | 2018 Acquisition [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	$ 1,700
Intangible assets amortization period	7 years
Sonoscan, Inc. [Member] | Trade Names [Member] | 2018 Acquisition [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	$ 3,300
Intangible assets amortization period	11 years
Sonoscan, Inc. [Member] | Technology-Based Intangible Assets [Member] | 2018 Acquisition [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	$ 2,500
Intangible assets amortization period	7 years
Sonoscan, Inc. [Member] | Non-compete Agreements [Member] | 2018 Acquisition [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	$ 410
Intangible assets amortization period	5 years
Vention [Member] | 2017 Acquisition [Member] | Term Loan Facility [Member]
Business Acquisition [Line Items]
Term loan facility		$ 705,000
Term loan facility due in September 2018		200,000
Term loan facility due in March 2020		200,000
Term loan facility due in March 2022		305,000
Weighted average interest rate for borrowings			2.99%	2.99%
Vention [Member] | 2017 Acquisition [Member] | Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired		705,000
Cash acquired from business acquisition		3,313
Goodwill		434,123
Identifiable intangible assets		286,000
Acquisition of businesses, Cash and other closing adjustments		10,726
Business combination, goodwill, tax deductible amount		37,200
Business acquisition material purchase price allocation adjustments			$ 0
Vention [Member] | Customer Relationships [Member] | 2017 Acquisition [Member] | Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$ 240,000
Intangible assets amortization period		14 years
Vention [Member] | Trade Names [Member] | 2017 Acquisition [Member] | Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$ 2,000
Intangible assets amortization period		6 years
Vention [Member] | Technology-Based Intangible Assets [Member] | 2017 Acquisition [Member] | Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$ 44,000
Vention [Member] | Technology-Based Intangible Assets Amortized over 14 Years [Member] | 2017 Acquisition [Member] | Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$ 36,000
Intangible assets amortization period		14 years
Vention [Member] | Technology-Based Intangible Assets Amortized over 10 Years [Member] | 2017 Acquisition [Member] | Advanced Technology Systems [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$ 8,000
Intangible assets amortization period		10 years