Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interest
Beginning Balance at Dec. 31, 2009	$ 290,427	$ 13,660	$ 22,458	$ 71,267	$ (31,951)	$ (25,893)	$ 250,973	$ 1,142
Consolidated Statements of Equity
Issuance of common stock under stock option plan	5,006		187	4,819
Acquisition of controlling interest in Stepan Philippines, Inc	2,090							2,090
Purchase of common stock	(7,155)				(7,155)
Conversion of preferred stock to common stock		(688)	60	628
Stock-based compensation	3,789		66	3,723
Deferred compensation	228			228
Net income	65,591						65,427	164
Other comprehensive income	478					294		184
Cash dividends paid:
Preferred stock	(747)						(747)
Common stock	(9,823)						(9,823)
Non-qualified stock option and stock award income tax benefit	3,187			3,187
Ending Balance at Dec. 31, 2010	353,071	13,002	11,512	83,852	(39,106)	(25,599)	305,830	3,580
Consolidated Statements of Equity
Issuance of common stock under stock option plan	3,796		134	3,662
Purchase of common stock	(4,112)				(4,112)
Conversion of preferred stock to common stock		(45)	2	43
Stock-based compensation	3,676		54	3,622
Deferred compensation	832		7	802	23
Net income	72,602						71,976	626
Other comprehensive income	(15,838)					(15,886)		48
Cash dividends paid:
Preferred stock	(714)						(714)
Common stock	(10,799)						(10,799)
Non-qualified stock option and stock award income tax benefit	2,951			2,951
Ending Balance at Dec. 31, 2011	405,465	12,957	11,709	94,932	(43,195)	(41,485)	366,293	4,254
Consolidated Statements of Equity
Issuance of common stock under stock option plan	8,806		321	8,485
Purchase of common stock	(11,759)				(11,759)
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest	(2,000)			551		197		(2,748)
Conversion of preferred stock to common stock		(11,409)	604	10,805
Stock-based compensation	2,484		42	2,442
Deferred compensation	581		6	551	24
Net income	79,687						79,396	291
Other comprehensive income	3,136					3,038		98
Cash dividends paid:
Preferred stock	(579)						(579)
Common stock	(12,178)						(12,178)
Non-qualified stock option and stock award income tax benefit	7,237			7,237
Two-for-one stock split			12,460				(12,460)
Ending Balance at Dec. 31, 2012	$ 480,880	$ 1,548	$ 25,142	$ 125,003	$ (54,930)	$ (38,250)	$ 420,472	$ 1,895