Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements of Income [Abstract]
Net Sales	$ 440,978	$ 499,335	$ 1,376,478	$ 1,398,922
Cost of Sales	369,725	435,255	1,155,045	1,203,471
Gross Profit	71,253	64,080	221,433	195,451
Operating Expenses:
Selling	12,128	10,885	38,764	33,886
Administrative	14,389	9,709	45,427	33,263
Research, development and technical services	10,845	10,083	33,130	30,970
Total Operating Expenses	37,362	30,677	117,321	98,119
Total operating income	33,891	33,403	104,112	97,332
Other Income (Expense):
Interest expense, net	(2,684)	(2,256)	(7,374)	(6,513)
Loss from equity in joint ventures	(1,376)	(890)	(3,817)	(2,660)
Other, net (Note 12)	404	(2,028)	1,552	(1,463)
Total Other Income (Expense)	(3,656)	(5,174)	(9,639)	(10,636)
Consolidated income before income taxes	30,235	28,229	94,473	86,696
Provision for Income Taxes	9,916	8,998	30,279	27,643
Net Income	20,319	19,231	64,194	59,053
Net Income Attributable to Noncontrolling Interests (Note 2)	(89)	(62)	(237)	(256)
Net Income Attributable to Stepan Company	$ 20,230	$ 19,169	$ 63,957	$ 58,797
Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	$ 1.90	$ 1.83	$ 6.01	$ 5.63
Diluted	$ 1.78	$ 1.70	$ 5.63	$ 5.25
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	10,581	10,365	10,553	10,345
Diluted	11,368	11,248	11,354	11,199
Dividends Declared Per Common Share	$ 0.28	$ 0.26	$ 0.84	$ 0.78