Segment Information - Disaggregation of revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 312,414	$ 298,504
North America [Member]
Disaggregation of Revenue [Line Items]
Revenues	236,294	211,250
Latin America [Member]
Disaggregation of Revenue [Line Items]
Revenues	12,443	14,134
EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenues	45,548	48,587
Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenues	18,129	24,533
On-Premises Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	93,998	109,657
SaaS Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	73,765	73,709
Scores Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	144,651	115,138
Scores
Disaggregation of Revenue [Line Items]
Revenues	144,651	115,138
Scores | North America [Member]
Disaggregation of Revenue [Line Items]
Revenues	140,410	110,197
Scores | Latin America [Member]
Disaggregation of Revenue [Line Items]
Revenues	303	284
Scores | EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,713	1,538
Scores | Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,225	3,119
Scores | On-Premises Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	0	0
Scores | SaaS Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	0	0
Scores | Scores Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	144,651	115,138
Decision Management Software
Disaggregation of Revenue [Line Items]
Revenues	32,402	31,188
Decision Management Software | North America [Member]
Disaggregation of Revenue [Line Items]
Revenues	16,547	15,587
Decision Management Software | Latin America [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,913	4,333
Decision Management Software | EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenues	8,578	7,265
Decision Management Software | Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenues	4,364	4,003
Decision Management Software | On-Premises Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	22,778	23,679
Decision Management Software | SaaS Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	9,624	7,509
Decision Management Software | Scores Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	0	0
Applications
Disaggregation of Revenue [Line Items]
Revenues	135,361	152,178
Applications | North America [Member]
Disaggregation of Revenue [Line Items]
Revenues	79,337	85,466
Applications | Latin America [Member]
Disaggregation of Revenue [Line Items]
Revenues	9,227	9,517
Applications | EMEA [Member]
Disaggregation of Revenue [Line Items]
Revenues	35,257	39,784
Applications | Asia Pacific [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,540	17,411
Applications | On-Premises Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	71,220	85,978
Applications | SaaS Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	64,141	66,200
Applications | Scores Products [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0
Revenue from Contract with Customer Benchmark [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
Revenue from Contract with Customer Benchmark [Member] | Scores
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	46.00%	39.00%
Revenue from Contract with Customer Benchmark [Member] | Decision Management Software
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	11.00%	10.00%
Revenue from Contract with Customer Benchmark [Member] | Applications
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	43.00%	51.00%