Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 40,611	$ 27,539
Other Comprehensive Income:
Foreign currency translation adjustments (Note 11)	[1]	(18,441)	(41,195)
Defined benefit pension adjustments, net of tax (Note 11)		874	808
Derivative instrument activity, net of tax (Note 11)		(2)	(2)
Total Other Comprehensive Income		(17,569)	(40,389)
Comprehensive Income		23,042	(12,850)
Comprehensive Income Attributable to Noncontrolling Interest (Note 2)		8	19
Comprehensive Income Attributable to Stepan Company		$ 23,050	$ (12,831)

[1] Includes foreign currency translation adjustments related to noncontrolling interest.