Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	[1]	$ 27,896	$ 28,501	$ 59,808	$ 56,420
Other comprehensive income (loss):
Foreign currency translation adjustments (Note 10)		5,997	(2,692)	16,451	9,898
Pension liability adjustment, net of tax (Note 10)		567	565	1,132	1,129
Derivative instrument activity, net of tax (Note 10)		(3)	(6)	(5)	(27)
Other comprehensive income (loss)		6,561	(2,133)	17,578	11,000
Comprehensive income		34,457	26,368	77,386	67,420
Comprehensive (income) loss attributable to noncontrolling interests (Note 2)		(34)	39	(46)	25
Comprehensive income attributable to Stepan Company		$ 34,423	$ 26,407	$ 77,340	$ 67,445

[1] The 2016 amounts for the noted items have been immaterially changed from the amounts originally reported as a result of the Company’s fourth quarter 2016 adoption of Accounting Standards Update (ASU) No. 2016-9, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting.