Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Segment revenues:
Total revenues	$ 380,266	$ 357,195	$ 725,136	$ 679,556
Segment operating expense	(220,505)	(205,138)	(425,036)	(411,913)
Operating income	159,761	152,057	300,100	267,643
Unallocated share-based compensation expense	(27,053)	(27,936)	(56,755)	(57,814)
Unallocated amortization expense	(275)	(543)	(550)	(1,087)
Unallocated interest expense	(23,897)	(17,211)	(46,697)	(29,406)
Unallocated other income, net	1,605	(2,361)	1,969	(932)
Income before income taxes	137,469	132,485	255,372	237,305
Depreciation expense	2,881	4,024	6,028	8,122
Gain on product line asset sale			1,941	0
Operating Segments
Segment revenues:
Segment operating expense	(193,177)	(176,659)	(369,672)	(353,012)
Operating income	187,089	180,536	355,464	326,544
Unallocated Corporate Expenses
Segment revenues:
Segment operating expense	(43,183)	(33,440)	(77,265)	(70,592)
Operating income	(43,183)	(33,440)	(77,265)	(70,592)
Depreciation expense	20	28	42	57
Scores
Segment revenues:
Total revenues	198,507	183,742	376,495	353,229
Scores | Operating Segments
Segment revenues:
Total revenues	198,507	183,742	376,495	353,229
Segment operating expense	(23,102)	(22,400)	(44,398)	(43,564)
Operating income	175,405	161,342	332,097	309,665
Depreciation expense	138	189	289	381
Software
Segment revenues:
Total revenues	181,759	173,453	348,641	326,327
Software | Operating Segments
Segment revenues:
Total revenues	181,759	173,453	348,641	326,327
Segment operating expense	(126,892)	(120,819)	(248,009)	(238,856)
Operating income	54,867	52,634	100,632	87,471
Depreciation expense	2,723	3,807	5,697	7,684
Professional services
Segment revenues:
Total revenues	27,175	24,365	49,497	50,901
Professional services | Operating Segments
Segment revenues:
Total revenues			49,497	50,901
Professional services | Scores | Operating Segments
Segment revenues:
Total revenues	0	0	0	0
Professional services | Software | Operating Segments
Segment revenues:
Total revenues	27,175	24,365	49,497	50,901
On-premises and SaaS software
Segment revenues:
Total revenues	154,584	149,088	299,144	275,426
On-premises and SaaS software | Operating Segments
Segment revenues:
Total revenues			299,144	275,426
On-premises and SaaS software | Scores | Operating Segments
Segment revenues:
Total revenues	0	0	0	0
On-premises and SaaS software | Software
Segment revenues:
Total revenues	154,584	149,088	299,144	275,426
On-premises and SaaS software | Software | Operating Segments
Segment revenues:
Total revenues	154,584	149,088	299,144	275,426
Scores
Segment revenues:
Total revenues	198,507	183,742	376,495	353,229
Scores | Operating Segments
Segment revenues:
Total revenues			376,495	353,229
Scores | Scores | Operating Segments
Segment revenues:
Total revenues	198,507	183,742	376,495	353,229
Scores | Software | Operating Segments
Segment revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0