Reconciliations of Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Reconciliations of total equity
Beginning Balance			$ 405,465	$ 353,071
Stockholders' Equity, Beginning Balance			401,211
Noncontrolling Interests' , Beginning Balance			4,254
Net income	20,319	19,231	64,194	59,053
Net income, Stepan Company Equity	20,230	19,169	63,957	58,797
Net income, Noncontrolling Interests'	89	62	237	256
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest			(2,000)
Dividends			(9,234)	(8,466)
Common stock purchases			(5,408)	(3,913)
Stock option exercises			4,645	3,111
Defined benefit pension adjustments, net of tax	512	389	1,676	1,433
Translation adjustments	5,513	(20,762)	3,493	(10,681)
Derivative instrument activity, net of tax	34	224	98	613
Other			4,829	6,106
Ending Balance	467,758	400,327	467,758	400,327
Stockholders' Equity, Ending Balance	465,953		465,953
Noncontrolling Interests' , Ending Balance	1,805		1,805
Noncontrolling Interest's Equity [Member]
Reconciliations of total equity
Noncontrolling Interests' , Beginning Balance			4,254	3,580
Net income, Noncontrolling Interests'			237	256
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest			(2,748)
Dividends
Common stock purchases
Stock option exercises
Defined benefit pension adjustments, net of tax
Translation adjustments, Noncontrolling Interests'			62	118
Derivative instrument activity, net of tax
Other
Noncontrolling Interests' , Ending Balance	1,805	3,954	1,805	3,954
Stepan Company Equity [Member]
Reconciliations of total equity
Stockholders' Equity, Beginning Balance			401,211	349,491
Net income, Stepan Company Equity			63,957	58,797
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest			748
Dividends			(9,234)	(8,466)
Common stock purchases			(5,408)	(3,913)
Stock option exercises			4,645	3,111
Defined benefit pension adjustments, net of tax			1,676	1,433
Translation adjustments, Stepan Company Equity			3,431	(10,799)
Derivative instrument activity, net of tax			98	613
Other			4,829	6,106
Stockholders' Equity, Ending Balance	$ 465,953	$ 396,373	$ 465,953	$ 396,373