Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 137,895	$ 127,656	$ 103,101
Other Comprehensive Income:
Foreign currency translation adjustments (Note 19)	(28,154)	(2,973)	4,425
Defined benefit pension plans:
Net actuarial gain (loss) arising in period (net of tax expense of $2,661, tax benefit of $265 and tax expense of $1,263 for 2021, 2020 and 2019, respectively)	8,188	(996)	4,112
Amortization of prior service cost included in pension expense (net of taxes of $4, $3 and $3 for 2021, 2020 and 2019, respectively)	8	8	9
Amortization of actuarial loss included in pension expense (net of taxes of $1,157, $1,089 and $657 for 2021, 2020 and 2019, respectively)	3,643	3,332	2,082
Net defined benefit pension plan activity (Note 19)	11,839	2,344	6,203
Cash flow hedges:
Reclassifications to income in period	(9)	(9)	(9)
Net cash flow hedge activity (Note 19)	(9)	(9)	(9)
Other Comprehensive Income	(16,324)	(638)	10,619
Comprehensive Income	121,571	127,018	113,720
Comprehensive Income Attributable to Noncontrolling Interest	(122)	(959)	47
Comprehensive Income Attributable to Stepan Company	$ 121,449	$ 126,059	$ 113,767