Goodwill and Intangible Assets - Summary of Changes to Goodwill (Detail) $ in Thousands	9 Months Ended
	Jun. 30, 2019 USD ($)
Goodwill [Roll Forward]
Balance at September 30, 2018	$ 800,890
Addition from acquisitions	980
Foreign currency translation adjustment	(4,343)
Balance at June 30, 2019	797,527
Applications
Goodwill [Roll Forward]
Balance at September 30, 2018	585,161
Addition from acquisitions	980
Foreign currency translation adjustment	(3,968)
Balance at June 30, 2019	582,173
Scores
Goodwill [Roll Forward]
Balance at September 30, 2018	146,648
Addition from acquisitions	0
Foreign currency translation adjustment	0
Balance at June 30, 2019	146,648
Decision Management Software
Goodwill [Roll Forward]
Balance at September 30, 2018	69,081
Addition from acquisitions	0
Foreign currency translation adjustment	(375)
Balance at June 30, 2019	$ 68,706