Reconciliations of Equity (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended
	May 22, 2012	Mar. 31, 2013	Mar. 31, 2012
Reconciliations of total equity
Beginning Balance		$ 480,880	$ 405,465
Beginning Balance		1,895
Beginning Balance		478,985
Net income		18,997	22,364
Net income		19,034	22,302
Net income		(37)	62
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest	2,000,000		(2,000)
Dividends		(3,542)	(3,072)
Common stock purchases		(1,059)	(1,761)
Stock option exercises		1,875	1,896
Pension liability adjustment, net of tax (Note 10)		863	582
Translation adjustments		(4,416)	8,534
Derivative instrument activity, net of tax (Note 10)		(12)	107
Other		1,303	2,567
Ending Balance		494,889	434,682
Ending Balance		493,029
Ending Balance		1,860
Stepan Company Equity [Member]
Reconciliations of total equity
Beginning Balance		478,985	401,211
Net income		19,034	22,302
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest			748
Dividends		(3,542)	(3,072)
Common stock purchases		(1,059)	(1,761)
Stock option exercises		1,875	1,896
Pension liability adjustment, net of tax (Note 10)		863	582
Translation adjustments		(4,418)	8,459
Derivative instrument activity, net of tax (Note 10)		(12)	107
Other		1,303	2,567
Ending Balance		493,029	433,039
Noncontrolling Interests' Equity [Member]
Reconciliations of total equity
Beginning Balance		1,895	4,254
Net income		(37)	62
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest			(2,748)
Dividends
Common stock purchases
Stock option exercises
Pension liability adjustment, net of tax (Note 10)
Translation adjustments		2	75
Derivative instrument activity, net of tax (Note 10)
Other
Ending Balance		$ 1,860	$ 1,643