Segment Information - Summary of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2013
Segment revenues:
Transactional and maintenance									$ 564,232		$ 527,563		$ 514,304
Professional services									151,773		149,834		135,194
License									122,776		111,588		93,946
Total revenues	$ 232,756	$ 209,366	$ 207,109	$ 189,550	$ 221,570	$ 197,610	$ 185,462	$ 184,343	838,781		788,985		743,444
Segment operating expense									(701,276)		(627,117)		(581,851)
Unallocated share-based compensation expense									(45,308)		(36,362)		(25,850)
Unallocated amortization expense	$ (1,900)	$ (1,900)	$ (1,900)	$ (1,800)	$ (1,900)	$ (1,900)	$ (1,800)	$ (1,800)	(13,673)	[1]	(11,917)	[1]	(13,535)	[1]
Unallocated restructuring and acquisition-related expenses									(18,242)		(4,281)		(3,486)
Operating income									137,505		161,868		161,593
Unallocated interest expense, net									(29,150)		(28,550)		(30,227)
Unallocated other income, net									883		(187)		618
Income before income taxes									109,238		133,131		131,984
Depreciation expense									20,216		20,715		19,679
Applications
Segment revenues:
Transactional and maintenance													306,738
Professional services													110,081
License													59,265
Total revenues									526,274		504,256		476,084
Scores
Segment revenues:
Transactional and maintenance													175,281
Professional services													4,012
License													1,520
Total revenues									207,007		186,469		180,813
Tools
Segment revenues:
Transactional and maintenance													32,285
Professional services													21,101
License													33,161
Total revenues									105,500		98,260		86,547
Operating Segments
Segment revenues:
Segment operating expense									(624,053)		(574,557)		(538,980)
Operating income									214,728		214,428		204,464
Operating Segments | Applications
Segment revenues:
Transactional and maintenance									320,596		313,316
Professional services									124,562		121,100
License									81,116		69,840
Total revenues									526,274
Segment operating expense									(366,666)		(334,762)		(334,953)
Operating income									159,608		169,494		141,131
Depreciation expense									13,861		14,451		14,171
Operating Segments | Scores
Segment revenues:
Transactional and maintenance									200,426		178,023
Professional services									2,901		2,784
License									3,680		5,662
Total revenues									207,007
Segment operating expense									(55,793)		(44,187)		(50,546)
Operating income									151,214		142,282		130,267
Depreciation expense									921		851		867
Operating Segments | Tools
Segment revenues:
Transactional and maintenance									43,210		36,224
Professional services									24,310		25,950
License									37,980		36,086
Total revenues									105,500
Segment operating expense									(111,850)		(94,057)		(67,078)
Operating income									(6,350)		4,203		19,469
Depreciation expense									3,087		2,752		1,998
Unallocated Corporate Expenses
Segment revenues:
Segment operating expense									(89,744)		(101,551)		(86,403)
Operating income									(89,744)		(101,551)		(86,403)
Depreciation expense									$ 2,347		$ 2,661		$ 2,643

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