Summary of Changes to Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended							12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Applications	Sep. 30, 2011 Applications	Sep. 30, 2012 Scores	Sep. 30, 2011 Scores	Sep. 30, 2010 Scores	Sep. 30, 2012 Tools	Sep. 30, 2011 Tools
Beginning Balance	$ 664,688	$ 665,953	$ 451,205	$ 452,248	$ 146,648	$ 146,648	$ 146,648	$ 66,835	$ 67,057
Addition from acquisition	87,280		87,280
Foreign currency translation adjustment	5,536	(1,265)	4,458	(1,043)				1,078	(222)
Ending Balance	$ 757,504	$ 664,688	$ 542,943	$ 451,205	$ 146,648	$ 146,648	$ 146,648	$ 67,913	$ 66,835