Goodwill and Intangible Assets - Summary of Changes to Goodwill (Detail) $ in Thousands	3 Months Ended
	Dec. 31, 2020 USD ($)
Goodwill [Roll Forward]
Balance at September 30, 2020	$ 812,364
Foreign currency translation adjustment	5,413
Balance at December 31, 2020	817,777
Applications
Goodwill [Roll Forward]
Balance at September 30, 2020	596,804
Foreign currency translation adjustment	4,568
Balance at December 31, 2020	601,372
Scores
Goodwill [Roll Forward]
Balance at September 30, 2020	146,648
Foreign currency translation adjustment	0
Balance at December 31, 2020	146,648
Decision Management Software
Goodwill [Roll Forward]
Balance at September 30, 2020	68,912
Foreign currency translation adjustment	845
Balance at December 31, 2020	$ 69,757