Subsequent Events	12 Months Ended
Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	26. Subsequent Events On January 29, 2021, the Company and its wholly-owned subsidiaries Stepan Holdings Netherlands B.V. and Stepan UK Limited (collectively, “Stepan”) entered into a Stock and Asset Purchase Agreement with Arteva Specialties B.V., INV Performance Surfaces, LLC, INVISTA Textiles (U.K.) Limited, INV Management Services, LLC, and INVISTA Equities, LLC (collectively, “INVISTA”) to acquire INVISTA's aromatic polyester polyol business and associated assets. Included in the transaction were two manufacturing sites, one in Wilmington, North Carolina (U.S.) and the other in Vlissingen, Netherlands, along with intellectual property, customer relationships, inventory and working capital. This acquisition expands the Company’s manufacturing capabilities in both the United States and Europe and enhances its business continuity capabilities for the market. The Company believes that INVISTA’s available spare capacity, combined with debottlenecking opportunities for both plants, will allow Stepan to support future market growth in a capital efficient way. The purchase price was $165,000,000, plus working capital, and was paid in cash. The allocation of the purchase price to reflect the fair value of assets acquired and liabilities assumed has not been completed at the date of the filing of this report. Such information will be included in a subsequent Quarterly Report on Form 10-Q. The acquisition will be accounted for as a business combination, and the acquired operations will be included in the Company’s Polymer segment beginning in the first quarter of 2021. On February 2, 2021, the Company acquired a fermentation plant, located in Lake Providence, Louisiana (U.S.). The Company believes this plant complements the rhamnolipid-based bio-surfactant technology the Company acquired from Logos Technologies in March 2020. Fermentation is a new platform technology for the Company and the Company is focusing efforts to further develop, integrate, produce and commercialize these unique surfactants moving forward. Bio-surfactants, produced via fermentation, are attractive due to their biodegradability, low toxicity, and in some cases, unique antimicrobial properties. These bio-surfactants offer synergies in several strategic end use markets including oilfield, agriculture, personal care and household, industrial and institutional. The acquisition of this industrial scale fermentation plant represents the latest step in the Company’s bio-surfactant commercialization efforts. The purchase price was $3,500,000 and was paid in cash. This acquisition will be accounted for as an asset acquisition.

Subsequent Events

12 Months Ended

Dec. 31, 2020

26. Subsequent Events

On January 29, 2021, the Company and its wholly-owned subsidiaries Stepan Holdings Netherlands B.V. and Stepan UK Limited (collectively, “Stepan”) entered into a Stock and Asset Purchase Agreement with Arteva Specialties B.V., INV Performance Surfaces, LLC, INVISTA Textiles (U.K.) Limited, INV Management Services, LLC, and INVISTA Equities, LLC (collectively, “INVISTA”) to acquire INVISTA's aromatic polyester polyol business and associated assets. Included in the transaction were two manufacturing sites, one in Wilmington, North Carolina (U.S.) and the other in Vlissingen, Netherlands, along with intellectual property, customer relationships, inventory and working capital. This acquisition expands the Company’s manufacturing capabilities in both the United States and Europe and enhances its business continuity capabilities for the market. The Company believes that INVISTA’s available spare capacity, combined with debottlenecking opportunities for both plants, will allow Stepan to support future market growth in a capital efficient way. The purchase price was $165,000,000, plus working capital, and was paid in cash. The allocation of the purchase price to reflect the fair value of assets acquired and liabilities assumed has not been completed at the date of the filing of this report. Such information will be included in a subsequent Quarterly Report on Form 10-Q. The acquisition will be accounted for as a business combination, and the acquired operations will be included in the Company’s Polymer segment beginning in the first quarter of 2021.

On February 2, 2021, the Company acquired a fermentation plant, located in Lake Providence, Louisiana (U.S.). The Company believes this plant complements the rhamnolipid-based bio-surfactant technology the Company acquired from Logos Technologies in March 2020. Fermentation is a new platform technology for the Company and the Company is focusing efforts to further develop, integrate, produce and commercialize these unique surfactants moving forward. Bio-surfactants, produced via fermentation, are attractive due to their biodegradability, low toxicity, and in some cases, unique antimicrobial properties. These bio-surfactants offer synergies in several strategic end use markets including oilfield, agriculture, personal care and household, industrial and institutional. The acquisition of this industrial scale fermentation plant represents the latest step in the Company’s bio-surfactant commercialization efforts. The purchase price was $3,500,000 and was paid in cash. This acquisition will be accounted for as an asset acquisition.