Document and Entity Information - $ / shares	6 Months Ended
	Jun. 30, 2019	Jul. 23, 2019
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	SCL
Entity Registrant Name	STEPAN CO
Entity Current Reporting Status	Yes
Entity Central Index Key	0000094049
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		22,556,992
Entity Tax Identification Number	361823834
Entity File Number	1-4462
Entity Address, Address Line One	Edens and Winnetka Road
Entity Address, City or Town	Northfield
Entity Address, State or Province	Illinois
Entity Address, Country	US
Entity Address, Postal Zip Code	60093
City Area Code	847
Local Phone Number	446-7500
New York Stock Exchange [Member]
Document Information [Line Items]
Entity Listing, Par Value Per Share	$ 1
Entity Listing, Description	Common Stock, $1 par value