Goodwill and Intangible Assets - Summary of Changes to Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Goodwill [Roll Forward]
Beginning Balance	$ 814,750	$ 779,928
Addition from acquisitions	3,857	46,149
Adjustment related to prior acquisitions	283
Foreign currency translation adjustment	(20,475)	(11,327)
Ending Balance	798,415	814,750
Applications
Goodwill [Roll Forward]
Beginning Balance	596,765	560,295
Addition from acquisitions	3,857	46,149
Adjustment related to prior acquisitions	283
Foreign currency translation adjustment	(18,185)	(9,679)
Ending Balance	582,720	596,765
Scores
Goodwill [Roll Forward]
Beginning Balance	146,648	146,648
Addition from acquisitions	0	0
Adjustment related to prior acquisitions	0
Foreign currency translation adjustment	0	0
Ending Balance	146,648	146,648
Decision Management Software
Goodwill [Roll Forward]
Beginning Balance	71,337	72,985
Addition from acquisitions	0	0
Adjustment related to prior acquisitions	0
Foreign currency translation adjustment	(2,290)	(1,648)
Ending Balance	$ 69,047	$ 71,337