Summary of Segment Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Segment revenues:
Transactional and maintenance									$ 527,563		$ 514,304		$ 466,175
Professional services									149,834		135,194		124,971
License									111,588		93,946		85,277
Total revenues	221,570	197,610	185,462	184,343	190,327	183,772	179,325	190,020	788,985		743,444		676,423
Segment operating expense									(627,117)		(581,851)		(508,065)
Unallocated share-based compensation expense									(36,362)		(25,850)		(21,229)
Unallocated amortization expense	(1,900)	(1,900)	(1,800)	(1,800)	(1,700)	(1,700)	(1,700)	(1,500)	(11,917)	[1]	(13,535)	[1]	(6,944)	[1]
Unallocated restructuring and acquisition-related									(4,281)		(3,486)		(5,125)
Operating income									161,868		161,593		168,358
Unallocated interest expense, net									(28,550)		(30,227)		(31,417)
Unallocated other expense, net									(187)		618		(698)
Income before income taxes									133,131		131,984		136,243
Depreciation expense									20,715		19,679		14,605
Applications
Segment revenues:
Transactional and maintenance									313,316		306,738		263,726
Professional services									121,100		110,081		104,637
License									69,840		59,265		56,241
Total revenues									504,256		476,084		424,604
Depreciation expense									14,451		14,171		11,321
Scores
Segment revenues:
Transactional and maintenance									178,023		175,281		172,218
Professional services									2,784		4,012		2,382
License									5,662		1,520		1,023
Total revenues									186,469		180,813		175,623
Depreciation expense									851		867		724
Tools
Segment revenues:
Transactional and maintenance									36,224		32,285		30,231
Professional services									25,950		21,101		17,952
License									36,086		33,161		28,013
Total revenues									98,260		86,547		76,196
Depreciation expense									2,752		1,998		1,258
Unallocated Corporate Expenses
Segment revenues:
Depreciation expense									2,661		2,643		1,302
Operating Segments
Segment revenues:
Segment operating expense									(574,557)		(538,980)		(474,767)
Operating income									214,428		204,464		201,656
Operating Segments | Applications
Segment revenues:
Segment operating expense									(334,762)		(334,953)		(285,488)
Operating income									169,494		141,131		139,116
Operating Segments | Scores
Segment revenues:
Segment operating expense									(44,187)		(50,546)		(51,998)
Operating income									142,282		130,267		123,625
Operating Segments | Tools
Segment revenues:
Segment operating expense									(94,057)		(67,078)		(56,960)
Operating income									4,203		19,469		19,236
Operating Segments | Unallocated Corporate Expenses
Segment revenues:
Segment operating expense									(101,551)		(86,403)		(80,321)
Operating income									$ (101,551)		$ (86,403)		$ (80,321)

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 7 to the consolidated financial statements.