Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands		3 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Segment revenues:
Transactional and maintenance		$ 174,662	$ 153,660
Professional services		42,626	43,543
License		18,033	22,397
Total revenues		235,321	219,600
Segment operating expense		(195,417)	(184,673)
Operating income		39,904	34,927
Unallocated share-based compensation expense		(16,510)	(14,519)
Unallocated amortization expense	[1]	(1,788)	(3,320)
Unallocated interest expense		(6,460)	(6,172)
Unallocated other income, net		513	(100)
Income before income taxes		33,957	28,655
Depreciation expense		5,794	5,609
Operating Segments
Segment revenues:
Segment operating expense		(177,119)	(166,834)
Operating income		58,202	52,766
Unallocated Corporate Expenses
Segment revenues:
Segment operating expense		(26,760)	(24,633)
Operating income		(26,760)	(24,633)
Depreciation expense		284	349
Applications | Operating Segments
Segment revenues:
Transactional and maintenance		93,213	84,881
Professional services		34,853	34,341
License		13,343	15,543
Total revenues		141,409	134,765
Segment operating expense		(102,619)	(99,797)
Operating income		38,790	34,968
Depreciation expense		3,943	3,868
Scores | Operating Segments
Segment revenues:
Transactional and maintenance		69,574	58,252
Professional services		278	521
License		63	609
Total revenues		69,915	59,382
Segment operating expense		(15,887)	(13,319)
Operating income		54,028	46,063
Depreciation expense		155	266
Decision Management Software | Operating Segments
Segment revenues:
Transactional and maintenance		11,875	10,527
Professional services		7,495	8,681
License		4,627	6,245
Total revenues		23,997	25,453
Segment operating expense		(31,853)	(29,085)
Operating income		(7,856)	(3,632)
Depreciation expense		$ 1,412	$ 1,126

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 4.