Revenue from Contracts with Customers - Disaggregated Revenue (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2025 USD ($) customer	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,990,869	$ 1,717,526	$ 1,513,557
Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	100.00%	100.00%	100.00%
Revenue from Contract with Customer Benchmark \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	100.00%	100.00%	100.00%
Revenue from Contract with Customer Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, number of customers \| customer	3
Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,168,575	$ 919,650	$ 773,828
Scores \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	100.00%	100.00%	100.00%
Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 822,294	$ 797,876	$ 739,729
TransUnion Equifax and Experian customers \| Revenue from Contract with Customer Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	51.00%	45.00%	41.00%
TransUnion \| Revenue from Contract with Customer Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	10.00%	10.00%	10.00%
Equifax \| Revenue from Contract with Customer Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	10.00%	10.00%	10.00%
Experian \| Revenue from Contract with Customer Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	10.00%	10.00%	10.00%
One Customer \| Accounts Receivable \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage		10.00%
Two Customers \| Accounts Receivable \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	10.00%
On-premises software \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	43.00%	44.00%	46.00%
On-premises software \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 320,425	$ 313,632	$ 292,763
SaaS software \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	57.00%	56.00%	54.00%
SaaS software \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 419,720	$ 397,708	$ 347,419
On-premises and SaaS software
Disaggregation of Revenue [Line Items]
Total revenues	$ 740,145	$ 711,340	$ 640,182
On-premises and SaaS software \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	100.00%	100.00%	100.00%
On-premises and SaaS software \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 740,145	$ 711,340	$ 640,182
On-premises and SaaS software \| Transferred at Point in Time \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	12.00%	11.00%	11.00%
On-premises and SaaS software \| Transferred at Point in Time \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 90,238	$ 76,284	$ 72,843
On-premises and SaaS software \| Transferred over Time \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	88.00%	89.00%	89.00%
On-premises and SaaS software \| Transferred over Time \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 649,907	$ 635,056	$ 567,339
Platform software \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	32.00%	28.00%	24.00%
Platform software \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 237,056	$ 200,004	$ 154,750
Non-platform software \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	68.00%	72.00%	76.00%
Non-platform software \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 503,089	$ 511,336	$ 485,432
Business-to-business Scores \| Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 948,595	$ 711,843	$ 560,995
Business-to-business Scores \| Scores \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	81.00%	77.00%	72.00%
Business-to-consumer Scores \| Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 219,980	$ 207,807	$ 212,833
Business-to-consumer Scores \| Scores \| Revenue from Contract with Customer Benchmark \| Product Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	19.00%	23.00%	28.00%
Americas
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,732,385	$ 1,449,888	$ 1,286,950
Americas \| Revenue from Contract with Customer Benchmark \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	87.00%	84.00%	85.00%
Americas \| Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,154,470	$ 905,266	$ 763,874
Americas \| Software
Disaggregation of Revenue [Line Items]
Total revenues	577,915	544,622	523,076
EMEA
Disaggregation of Revenue [Line Items]
Total revenues	$ 159,803	$ 169,526	$ 141,364
EMEA \| Revenue from Contract with Customer Benchmark \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	8.00%	10.00%	9.00%
EMEA \| Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 6,984	$ 5,908	$ 5,802
EMEA \| Software
Disaggregation of Revenue [Line Items]
Total revenues	152,819	163,618	135,562
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	$ 98,681	$ 98,112	$ 85,243
Asia Pacific \| Revenue from Contract with Customer Benchmark \| Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Percentage	5.00%	6.00%	6.00%
Asia Pacific \| Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 7,121	$ 8,476	$ 4,152
Asia Pacific \| Software
Disaggregation of Revenue [Line Items]
Total revenues	$ 91,560	$ 89,636	$ 81,091