Revenue from Contracts with Customers Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 262,256	$ 232,361
Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	235,001	213,531
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	27,255	18,830
Applications
Disaggregation of Revenue [Line Items]
Revenues	147,659	140,174
Applications | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	128,627	126,500
Applications | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	19,032	13,674
Scores
Disaggregation of Revenue [Line Items]
Revenues	85,683	68,431
Scores | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	85,522	68,293
Scores | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	161	138
Decision Management Software
Disaggregation of Revenue [Line Items]
Revenues	28,914	23,756
Decision Management Software | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	20,852	18,738
Decision Management Software | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	8,062	5,018
North America
Disaggregation of Revenue [Line Items]
Revenues	176,846	163,418
North America | Applications
Disaggregation of Revenue [Line Items]
Revenues	80,949	83,739
North America | Scores
Disaggregation of Revenue [Line Items]
Revenues	82,073	66,613
North America | Decision Management Software
Disaggregation of Revenue [Line Items]
Revenues	13,824	13,066
Latin America
Disaggregation of Revenue [Line Items]
Revenues	23,992	7,686
Latin America | Applications
Disaggregation of Revenue [Line Items]
Revenues	18,253	5,633
Latin America | Scores
Disaggregation of Revenue [Line Items]
Revenues	514	709
Latin America | Decision Management Software
Disaggregation of Revenue [Line Items]
Revenues	5,225	1,344
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenues	40,220	42,796
Europe, Middle East and Africa | Applications
Disaggregation of Revenue [Line Items]
Revenues	32,562	36,216
Europe, Middle East and Africa | Scores
Disaggregation of Revenue [Line Items]
Revenues	1,534	858
Europe, Middle East and Africa | Decision Management Software
Disaggregation of Revenue [Line Items]
Revenues	6,124	5,722
Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues	21,198	18,461
Asia Pacific | Applications
Disaggregation of Revenue [Line Items]
Revenues	15,895	14,586
Asia Pacific | Scores
Disaggregation of Revenue [Line Items]
Revenues	1,562	251
Asia Pacific | Decision Management Software
Disaggregation of Revenue [Line Items]
Revenues	$ 3,741	$ 3,624