Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Net Sales	$ 491,429	$ 475,466	$ 1,472,982	$ 1,406,457
Cost of Sales	426,330	401,125	1,273,270	1,185,709
Gross Profit	65,099	74,341	199,712	220,748
Operating Expenses:
Selling	16,816	12,895	44,455	41,063
Administrative	14,933	18,127	38,416	49,008
Research, development and technical services	11,097	12,234	35,151	35,429
Total Operating expenses	42,846	43,256	118,022	125,500
Operating Income	22,253	31,085	81,690	95,248
Other Income (Expense):
Interest, net	(2,846)	(2,987)	(8,824)	(7,495)
Loss from equity in joint ventures	(1,148)	(1,325)	(3,842)	(4,061)
Other, net (Note 13)	(31)	1,074	499	1,628
Nonoperating Income (Expense), Total	(4,025)	(3,238)	(12,167)	(9,928)
Income Before Provision for Income Taxes	18,228	27,847	69,523	85,320
Provision for Income Taxes	4,748	7,698	18,667	23,520
Net Income	13,480	20,149	50,856	61,800
Net Loss Attributable to Noncontrolling Interests (Note 2)	11	253	6	378
Net Income Attributable to Stepan Company	$ 13,491	$ 20,402	$ 50,862	$ 62,178
Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	$ 0.59	$ 0.90	$ 2.24	$ 2.75
Diluted	$ 0.59	$ 0.89	$ 2.22	$ 2.71
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic	22,726	22,700	22,754	22,576
Diluted	22,875	22,936	22,923	22,914
Dividends Declared Per Common Share	$ 0.17	$ 0.16	$ 0.51	$ 0.48