Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net Sales	$ 444,011	$ 491,429	$ 1,356,876	$ 1,472,982
Cost of Sales	366,413	426,330	1,123,324	1,273,270
Gross Profit	77,598	65,099	233,552	199,712
Operating Expenses:
Selling	14,025	16,816	41,287	44,455
Administrative	12,154	14,933	55,548	38,416
Research, development and technical services	12,625	11,097	37,012	35,151
Total Operating expenses	38,804	42,846	133,847	118,022
Gain on sale of product line			2,862
Operating Income	38,794	22,253	102,567	81,690
Other Income (Expense):
Interest, net	(3,837)	(2,846)	(10,760)	(8,824)
Loss from equity in joint ventures	(863)	(1,148)	(3,918)	(3,842)
Other, net (Note 13)	(981)	(31)	(94)	499
Nonoperating Income (Expense), Total	(5,681)	(4,025)	(14,772)	(12,167)
Income Before Provision for Income Taxes	33,113	18,228	87,795	69,523
Provision for Income Taxes	8,179	4,748	24,634	18,667
Net Income	24,934	13,480	63,161	50,856
Net (Income) Loss Attributable to Noncontrolling Interests (Note 2)	(22)	11	(65)	6
Net Income Attributable to Stepan Company	$ 24,912	$ 13,491	$ 63,096	$ 50,862
Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	$ 1.10	$ 0.59	$ 2.78	$ 2.24
Diluted	$ 1.09	$ 0.59	$ 2.76	$ 2.22
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	22,732	22,726	22,731	22,754
Diluted	22,853	22,875	22,851	22,923
Dividends Declared Per Common Share	$ 0.18	$ 0.17	$ 0.54	$ 0.51