Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Condensed Consolidated Statements of Income [Abstract]
Net Sales	$ 456,546	$ 465,269
Cost of Sales	383,846	388,485
Gross Profit	72,700	76,784
Operating Expenses:
Selling	13,728	13,651
Administrative	19,351	16,952
Research, development and technical services	11,327	10,781
Total Operating Expenses	44,406	41,384
Operating Income	28,294	35,400
Other Income (Expense):
Interest, net	(2,179)	(2,604)
Loss from equity in joint ventures	(1,413)	(1,141)
Other, net (Note 13)	571	1,065
Total Other Income (Expense)	(3,021)	(2,680)
Income Before Provision for Income Taxes	25,273	32,720
Provision for Income Taxes	6,276	10,356
Net Income	18,997	22,364
Net (Income) Loss Attributable to Noncontrolling Interests (Note 2)	37	(62)
Net Income Attributable to Stepan Company	$ 19,034	$ 22,302
Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	$ 0.85	$ 1.05
Diluted	$ 0.83	$ 0.98
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	22,464	21,022
Diluted	22,887	22,642
Dividends Declared Per Common Share	$ 0.16	$ 0.14