Summary of Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2015		Mar. 31, 2014
Segment revenues:
Transactional and maintenance	$ 138,683		$ 132,369		$ 270,093		$ 262,024
Professional services	37,946		34,619		73,144		68,905
License	30,480		18,474		53,422		38,876
Total revenues	207,109		185,462		396,659		369,805
Segment operating expense	(172,710)		(146,725)		(337,380)		(295,798)
Unallocated share-based compensation expense	(11,802)		(9,051)		(20,596)		(16,286)
Unallocated amortization expense	(3,515)	[1]	(2,908)	[1]	(6,447)	[1]	(5,921)	[1]
Unallocated restructuring and acquisition-related	0		0		0		(3,660)
Operating income	34,399		38,737		59,279		74,007
Unallocated interest expense	(7,718)		(7,099)		(14,923)		(14,225)
Unallocated other income (expense), net	(648)		(351)		1		(1,312)
Income before income taxes	26,033		31,287		44,357		58,470
Depreciation expense	5,425		4,937		10,600		10,091
Operating Segments
Segment revenues:
Segment operating expense	(157,393)		(134,766)		(310,337)		(269,931)
Operating income	49,716		50,696		86,322		99,874
Applications
Segment revenues:
Transactional and maintenance	80,315		76,898		158,866		154,677
Professional services	30,992		28,373		59,491		55,160
License	23,081		10,339		31,529		17,689
Total revenues	134,388		115,610		249,886		227,526
Depreciation expense	3,706		3,461		7,214		7,098
Applications | Operating Segments
Segment revenues:
Segment operating expense	(95,035)		(78,951)		(183,929)		(160,913)
Operating income	39,353		36,659		65,957		66,613
Scores
Segment revenues:
Transactional and maintenance	47,814		46,560		90,751		89,878
Professional services	966		777		1,754		1,366
License	1,157		521		1,373		3,794
Total revenues	49,937		47,858		93,878		95,038
Depreciation expense	227		198		444		410
Scores | Operating Segments
Segment revenues:
Segment operating expense	(14,618)		(10,939)		(27,510)		(21,314)
Operating income	35,319		36,919		66,368		73,724
Tools
Segment revenues:
Transactional and maintenance	10,554		8,911		20,476		17,469
Professional services	5,988		5,469		11,899		12,379
License	6,242		7,614		20,520		17,393
Total revenues	22,784		21,994		52,895		47,241
Depreciation expense	807		622		1,590		1,236
Tools | Operating Segments
Segment revenues:
Segment operating expense	(27,987)		(20,804)		(57,526)		(41,875)
Operating income	(5,203)		1,190		(4,631)		5,366
Unallocated Corporate Expenses
Segment revenues:
Total revenues					0		0
Depreciation expense	685		656		1,352		1,347
Unallocated Corporate Expenses | Operating Segments
Segment revenues:
Segment operating expense	(19,753)		(24,072)		(41,372)		(45,829)
Operating income	$ (19,753)		$ (24,072)		$ (41,372)		$ (45,829)

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 5 to the condensed consolidated financial statements.