Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2018	Nov. 15, 2018	Apr. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Entity Registrant Name	PTC Inc.
Entity Central Index Key	0000857005
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		118,675,240
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 8,976,658,598