Revenue from Contracts with Customers - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2025	Dec. 31, 2024	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Contract assets	$ 0	$ 0
Contract liabilities	282,000	$ 689,000
Contract liabilities revenue recorded	689,000
Long term deferred revenue			$ 10,709,000
Pre-existing Contract Liabilities [Member]
Disaggregation Of Revenue [Line Items]
Contract liabilities revenue recorded	5,724,000
Long-Term [Member]
Disaggregation Of Revenue [Line Items]
Long term deferred revenue	2,769,000
Short-Term [Member]
Disaggregation Of Revenue [Line Items]
Short-term defferred revenue	$ 2,216,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

STEPAN CO 10-Q