Disaggregation of Revenue (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2023 USD ($) Segment customer	Dec. 31, 2022 USD ($) Segment	Sep. 30, 2023 customer
Disaggregation of Revenue [Line Items]
Total revenues	$ 382,059	$ 344,870
Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
Revenue from Contract with Customer Benchmark [Member] | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
Revenue from Contract with Customer Benchmark [Member] | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Revenue, Number of Customers | Segment	(3)	(2)
Revenue from Contract with Customer Benchmark [Member] | Customer Concentration Risk | TransUnion, Equifax and Experian customers
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	39.00%	36.00%
Accounts Receivable | Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Receivables, Number of Customers | customer	1		1
On-premises and SaaS software
Disaggregation of Revenue [Line Items]
Total revenues	$ 168,668	$ 144,560
On-premises and SaaS software | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
On-premises and SaaS software | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	8.00%	8.00%
On-premises and SaaS software | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk | Transferred over Time
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	92.00%	92.00%
On-Premises | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	43.00%	45.00%
SaaS Products | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	57.00%	55.00%
Platform software | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	27.00%	21.00%
Non-platform software | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	73.00%	79.00%
Americas
Disaggregation of Revenue [Line Items]
Total revenues	$ 318,510	$ 291,127
Americas | Revenue from Contract with Customer Benchmark [Member] | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	83.00%	85.00%
EMEA
Disaggregation of Revenue [Line Items]
Total revenues	$ 36,368	$ 32,340
EMEA | Revenue from Contract with Customer Benchmark [Member] | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	10.00%	9.00%
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	$ 27,181	$ 21,403
Asia Pacific | Revenue from Contract with Customer Benchmark [Member] | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	7.00%	6.00%
Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 192,112	$ 177,988
Scores | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
Scores | Business to business Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 140,442	$ 124,905
Scores | Business to business Scores | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	73.00%	70.00%
Scores | Business to consumer Scores
Disaggregation of Revenue [Line Items]
Total revenues	$ 51,670	$ 53,083
Scores | Business to consumer Scores | Revenue from Contract with Customer Benchmark [Member] | Product Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	27.00%	30.00%
Scores | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	$ 192,112	$ 177,988
Scores | Operating Segments | On-premises and SaaS software
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Scores | Americas
Disaggregation of Revenue [Line Items]
Total revenues	184,948	173,297
Scores | EMEA
Disaggregation of Revenue [Line Items]
Total revenues	1,308	1,348
Scores | Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	5,856	3,343
Software
Disaggregation of Revenue [Line Items]
Total revenues	189,947	166,882
Software | On-premises and SaaS software
Disaggregation of Revenue [Line Items]
Total revenues	168,668	144,560
Software | On-premises and SaaS software | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Total revenues	13,782	11,803
Software | On-premises and SaaS software | Transferred over Time
Disaggregation of Revenue [Line Items]
Total revenues	154,886	132,757
Software | On-Premises
Disaggregation of Revenue [Line Items]
Total revenues	72,472	64,922
Software | SaaS Products
Disaggregation of Revenue [Line Items]
Total revenues	96,196	79,638
Software | Platform software
Disaggregation of Revenue [Line Items]
Total revenues	45,173	30,828
Software | Non-platform software
Disaggregation of Revenue [Line Items]
Total revenues	123,495	113,732
Software | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	189,947	166,882
Software | Operating Segments | On-premises and SaaS software
Disaggregation of Revenue [Line Items]
Total revenues	168,668	144,560
Software | Americas
Disaggregation of Revenue [Line Items]
Total revenues	133,562	117,830
Software | EMEA
Disaggregation of Revenue [Line Items]
Total revenues	35,060	30,992
Software | Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	$ 21,325	$ 18,060