Business Combinations (Narrative) (Details) business in Thousands		3 Months Ended			9 Months Ended
	Apr. 30, 2019 USD ($) business	Aug. 31, 2019 USD ($)	Aug. 31, 2018 USD ($)		Aug. 31, 2019 USD ($)	Aug. 31, 2018 USD ($)		Nov. 30, 2018 USD ($)	[1]
Business Acquisition [Line Items]
Goodwill		$ 432,598,000			$ 432,598,000			$ 314,992,000
Stock-based compensation expense		5,490,000	$ 4,566,000		17,411,000	$ 14,716,000
Acquisition-related expenses		253,000	$ 42,000	[2]	1,360,000	$ 128,000	[2]
Acquired intangible assets		111,300,000			$ 111,300,000
Effective income tax rate					24.50%
Ipswitch
Business Acquisition [Line Items]
Total purchase consideration	$ 225,000,000.0
Escrow deposit	$ 22,500,000
Number of small and medium-sized businesses | business	24
Goodwill	$ 117,651,000
Ipswitch | Restricted Stock Units
Business Acquisition [Line Items]
Equity interest issued	$ 2,000,000.0
Period of non-compete agreement	3 years
Intangible assets amortization period	3 years
Stock-based compensation expense		200,000			$ 200,000
Acquisition-related expenses		300,000			1,400,000
Revenue of acquisition		$ 10,700,000			$ 14,000,000.0
Term Loan | Ipswitch
Business Acquisition [Line Items]
Term loan	$ 185,000,000.0
Term loan and maximum borrowing capacity	401,000,000.0
Customer-related | Ipswitch
Business Acquisition [Line Items]
Finite-lived intangible assets	66,600,000
Purchased technology | Ipswitch
Business Acquisition [Line Items]
Finite-lived intangible assets	33,100,000
Trade name | Ipswitch
Business Acquisition [Line Items]
Finite-lived intangible assets	$ 9,600,000

[1] The Company adopted the accounting standard related to revenue recognition ("ASC 606") effective December 1, 2018 using the full retrospective method. See Note 1. Nature of Business and Basis of Presentation for further information.

[2] The Company adopted ASC 606 effective December 1, 2018 using the full retrospective method. See Note 1. Nature of Business and Basis of Presentation for further information.