Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment revenues:
Total revenues	$ 398,688	$ 348,966	$ 1,123,824	$ 1,028,522
Segment operating expense	(221,657)	(208,351)	(646,693)	(620,264)
Operating income	177,031	140,615	477,131	408,258
Unallocated share-based compensation expense	(32,995)	(28,549)	(89,750)	(86,363)
Unallocated amortization expense	(275)	(532)	(825)	(1,619)
Unallocated interest expense	(24,545)	(18,721)	(71,242)	(48,127)
Unallocated other income, net	5,301	(1,000)	7,270	(1,932)
Income before income taxes	157,787	120,894	413,159	358,199
Depreciation expense	2,216	3,773	8,244	11,895
Gain on product line asset sale			1,941	0
Operating Segments
Segment revenues:
Segment operating expense	(188,387)	(179,270)	(558,059)	(532,282)
Operating income	210,301	169,696	565,765	496,240
Unallocated Corporate Expenses
Segment revenues:
Segment operating expense	(42,347)	(34,142)	(119,612)	(104,734)
Operating income	(42,347)	(34,142)	(119,612)	(104,734)
Depreciation expense	16	26	58	83
Scores
Segment revenues:
Total revenues	201,778	179,355	578,273	532,584
Scores | Operating Segments
Segment revenues:
Total revenues	201,778	179,355	578,273	532,584
Segment operating expense	(24,779)	(21,547)	(69,177)	(65,111)
Operating income	176,999	157,808	509,096	467,473
Depreciation expense	107	182	396	563
Software
Segment revenues:
Total revenues	196,910	169,611	545,551	495,938
Software | Operating Segments
Segment revenues:
Total revenues	196,910	169,611	545,551	495,938
Segment operating expense	(121,261)	(123,581)	(369,270)	(362,437)
Operating income	75,649	46,030	176,281	133,501
Depreciation expense	2,093	3,565	7,790	11,249
Professional services
Segment revenues:
Total revenues	24,851	27,074	74,348	77,975
Professional services | Operating Segments
Segment revenues:
Total revenues			74,348	77,975
Professional services | Scores | Operating Segments
Segment revenues:
Total revenues	0	0	0	0
Professional services | Software | Operating Segments
Segment revenues:
Total revenues	24,851	27,074	74,348	77,975
On-premises and SaaS software
Segment revenues:
Total revenues	172,059	142,537	471,203	417,963
On-premises and SaaS software | Operating Segments
Segment revenues:
Total revenues			471,203	417,963
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	172,059	142,537	471,203	417,963
On-premises and SaaS software | Software | Operating Segments
Segment revenues:
Total revenues	172,059	142,537	471,203	417,963
Scores
Segment revenues:
Total revenues	201,778	179,355	578,273	532,584
Scores | Operating Segments
Segment revenues:
Total revenues			578,273	532,584
Scores | Scores | Operating Segments
Segment revenues:
Total revenues	201,778	179,355	578,273	532,584
Scores | Software | Operating Segments
Segment revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0