Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Segment revenues:
Total revenues	$ 357,195	$ 331,361	$ 679,556	$ 643,775
Segment operating expense	(205,138)	(230,162)	(411,913)	(447,855)
Operating income	152,057	101,199	267,643	195,920
Unallocated share-based compensation expense	(27,936)	(28,206)	(57,814)	(53,338)
Unallocated amortization expense	(543)	(945)	(1,087)	(1,882)
Unallocated interest expense	(17,211)	(9,943)	(29,406)	(19,584)
Unallocated other expense, net	(2,361)	568	(932)	3,448
Income before income taxes	132,485	91,824	237,305	179,784
Depreciation expense	4,024	5,224	8,122	10,809
Gains on product line asset sales and business divestiture	0	0	0	7,334
Operating Segments
Segment revenues:
Segment operating expense	(176,659)	(201,011)	(353,012)	(399,969)
Operating income	180,536	130,350	326,544	243,806
Unallocated Corporate Expenses
Segment revenues:
Segment operating expense	(35,680)	(33,392)	(71,468)	(63,645)
Operating income	(35,680)	(33,392)	(71,468)	(63,645)
Depreciation expense	28	45	57	78
Scores
Segment revenues:
Total revenues	183,742	168,719	353,229	313,370
Scores | Operating Segments
Segment revenues:
Total revenues	183,742	168,719	353,229	313,370
Segment operating expense	(21,026)	(22,177)	(43,010)	(43,803)
Operating income	162,716	146,542	310,219	269,567
Depreciation expense	189	167	381	361
Software
Segment revenues:
Total revenues	173,453	162,642	326,327	330,405
Software | Operating Segments
Segment revenues:
Total revenues	173,453	162,642	326,327	330,405
Segment operating expense	(119,953)	(145,442)	(238,534)	(292,521)
Operating income	53,500	17,200	87,793	37,884
Depreciation expense	3,807	5,012	7,684	10,370
Professional services
Segment revenues:
Total revenues	24,365	37,091	50,901	78,399
Professional services | Operating Segments
Segment revenues:
Total revenues			50,901	78,399
Professional services | Scores | Operating Segments
Segment revenues:
Total revenues	0	0	0	0
Professional services | Software | Operating Segments
Segment revenues:
Total revenues	24,365	37,091	50,901	78,399
On-premises and SaaS software
Segment revenues:
Total revenues	149,088	125,551	275,426	252,006
On-premises and SaaS software | Operating Segments
Segment revenues:
Total revenues			275,426	252,006
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	149,088	125,551	275,426	252,006
On-premises and SaaS software | Software | Operating Segments
Segment revenues:
Total revenues	149,088	125,551	275,426	252,006
Scores
Segment revenues:
Total revenues	183,742	168,719	353,229	313,370
Scores | Operating Segments
Segment revenues:
Total revenues			353,229	313,370
Scores | Scores | Operating Segments
Segment revenues:
Total revenues	183,742	168,719	353,229	313,370
Scores | Software | Operating Segments
Segment revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0