Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Segment revenues:
Total revenues	$ 322,361	$ 312,414
Segment operating expense	(206,775)	(217,693)
Operating income	115,586	94,721
Unallocated share-based compensation expense	(29,878)	(25,132)
Unallocated amortization expense	(544)	(937)
Unallocated interest expense	(12,195)	(9,641)
Unallocated other income, net	1,429	2,880
Income before income taxes	104,820	87,960
Depreciation expense	4,098	5,585
Gains on product line asset sales and business divestiture	0	7,334
Operating Segments
Segment revenues:
Segment operating expense	(176,353)	(198,958)
Operating income	146,008	113,456
Unallocated Corporate Expenses
Segment revenues:
Segment operating expense	(35,788)	(30,253)
Operating income	(35,788)	(30,253)
Depreciation expense	29	33
Scores
Segment revenues:
Total revenues	169,487	144,651
Scores | Operating Segments
Segment revenues:
Total revenues	169,487	144,651
Segment operating expense	(21,984)	(21,626)
Operating income	147,503	123,025
Depreciation expense	192	194
Software
Segment revenues:
Total revenues	152,874	167,763
Software | Operating Segments
Segment revenues:
Total revenues	152,874	167,763
Segment operating expense	(118,581)	(147,079)
Operating income	34,293	20,684
Depreciation expense	3,877	5,358
Professional services
Segment revenues:
Total revenues	26,536	41,308
Professional services | Scores | Operating Segments
Segment revenues:
Total revenues	0	0
Professional services | Software | Operating Segments
Segment revenues:
Total revenues	26,536	41,308
On-premises and SaaS software
Segment revenues:
Total revenues	126,338	126,455
On-premises and SaaS software | Scores | Operating Segments
Segment revenues:
Total revenues	0	0
On-premises and SaaS software | Software
Segment revenues:
Total revenues	126,338	126,455
On-premises and SaaS software | Software | Operating Segments
Segment revenues:
Total revenues	126,338	126,455
Scores
Segment revenues:
Total revenues	169,487	144,651
Scores | Scores | Operating Segments
Segment revenues:
Total revenues	169,487	144,651
Scores | Software | Operating Segments
Segment revenues:
Total revenues	$ 0	$ 0