Business Combinations (Narrative) (Details) business in Thousands		3 Months Ended		6 Months Ended
	Apr. 30, 2019 USD ($) business	May 31, 2020 USD ($)	May 31, 2019 USD ($)	May 31, 2020 USD ($)	May 31, 2019 USD ($)	Nov. 30, 2019 USD ($)
Business Acquisition [Line Items]
Increase (decrease) in measurement period adjustments				$ (838,000)
Goodwill		$ 431,869,000		431,869,000		$ 432,824,000
Stock-based compensation expense		5,623,000	$ 6,116,000	11,674,000	$ 11,922,000
Acquisition-related expenses		0	1,107,000	314,000	1,107,000
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
Increase (decrease) in measurement period adjustments	$ (618,000)	(600,000)
Goodwill	117,033,000
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				$ 300,000
Acquisition-related expenses		300,000		300,000
Revenue of acquisition		$ 17,300,000	$ 3,300,000	$ 32,500,000	$ 3,300,000
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