Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2017	Nov. 27, 2017	Apr. 01, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Entity Registrant Name	PTC Inc.
Entity Central Index Key	0000857005
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		116,125,277	115,807,774
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 6,020,802,164