Consolidated Statements of Equity (USD $) In Thousands, unless otherwise specified	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interests' Equity [Member]
Balance at Dec. 31, 2011	$ 405,465	$ 12,957	$ 11,709	$ 94,932	$ (43,195)	$ (41,485)	$ 366,293	$ 4,254
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 and deferred compensation	3,065		48	2,993	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)
Balance at Dec. 31, 2012	480,880	1,548	25,142	125,003	(54,930)	(38,250)	420,472	1,895
Issuance of common stock under stock option plan	4,069		227	3,842
Purchase of common stock	(3,425)				(3,425)
Redemption of preferred stock	(21)	(21)
Conversion of preferred stock to common stock		(1,527)	140	1,387
Stock-based and deferred compensation	2,162		55	2,021	86
Net Income	72,337						72,828	(491)
Other comprehensive income	8,773					8,722		51
Cash dividends paid:
Preferred stock	(43)						(43)
Common stock	(14,431)						(14,431)
Non-qualified stock option and stock award income tax benefit	3,440			3,440
Balance at Dec. 31, 2013	553,741		25,564	135,693	(58,269)	(29,528)	478,826	1,455
Issuance of common stock under stock option plan	1,754		67	1,687
Purchase of common stock	(7,924)				(7,924)
Stock-based and deferred compensation	1,493		9	1,553	(69)
Net Income	57,081						57,101	(20)
Other comprehensive income	(54,454)					(54,417)		(37)
Cash dividends paid:
Common stock	(15,387)						(15,387)
Non-qualified stock option and stock award income tax benefit	640			640
Balance at Dec. 31, 2014	$ 536,944		$ 25,640	$ 139,573	$ (66,262)	$ (83,945)	$ 520,540	$ 1,398