Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net Sales		$ 445,030	$ 444,011	$ 1,345,530	$ 1,356,876
Cost of Sales		361,635	366,413	1,075,705	1,123,324
Gross Profit		83,395	77,598	269,825	233,552
Operating Expenses:
Selling		13,990	14,025	42,252	41,287
Administrative	[1]	18,958	19,076	55,350	54,320
Research, development and technical services		14,268	12,625	42,306	37,012
Deferred compensation expense (income)	[1]	7,441	(6,922)	12,595	1,228
Total Operating expenses		54,657	38,804	152,503	133,847
Gain on sale of product line					2,862
Business restructuring				(1,061)
Operating Income		28,738	38,794	116,261	102,567
Other Income (Expense):
Interest, net		(2,824)	(3,837)	(9,855)	(10,760)
Loss from equity in joint ventures (Note 16)			(863)		(3,918)
Other, net (Note 13)		1,229	(981)	401	(94)
Nonoperating Income (Expense), Total		(1,595)	(5,681)	(9,454)	(14,772)
Income Before Provision for Income Taxes		27,143	33,113	106,807	87,795
Provision for Income Taxes		6,711	8,179	30,848	24,634
Net Income		20,432	24,934	75,959	63,161
Net Income Attributable to Noncontrolling Interests (Note 2)		(5)	(22)	(13)	(65)
Net Income Attributable to Stepan Company		$ 20,427	$ 24,912	$ 75,946	$ 63,096
Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic		$ 0.90	$ 1.10	$ 3.34	$ 2.78
Diluted		$ 0.89	$ 1.09	$ 3.31	$ 2.76
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic		22,819	22,732	22,771	22,731
Diluted		23,082	22,853	22,975	22,851
Dividends Declared Per Common Share		$ 0.19	$ 0.18	$ 0.57	$ 0.54

[1] For the three and nine months ended September 30, 2015, deferred compensation expense (income) was included in the administrative expense line. The 2015 amounts have been classified separately to conform to the current year presentation.