Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Balance at December 31, 2012	$ (38,250)
Foreign currency translation adjustments (Note 10)	(4,416)	8,534
Net current-period other comprehensive income, Defined Benefit Pension Plan Adjustments	863	582
Net current-period other comprehensive income, Cash Flow Hedge Adjustments	(12)	107
Net current-period other comprehensive income, Total	(3,565)	9,223
Accumulated Other Comprehensive Income (Loss), Balance at March 31, 2013	(41,817)
Stepan Company Equity [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Balance at December 31, 2012	(2,886)
Accumulated Other Comprehensive Income (Loss), Defined Benefit Pension Plan Adjustments, Balance at December 31, 2012	(35,498)
Accumulated Other Comprehensive Income (Loss), Cash Flow Hedge Adjustments, Balance at December 31, 2012	134
Accumulated Other Comprehensive Income (Loss), Balance at December 31, 2012	(38,250)
Other comprehensive income before reclassifications, Foreign Currency Translation Adjustments	(4,418)
Other comprehensive income before reclassifications, Defined Benefit Pension Plan Adjustments
Other comprehensive income before reclassifications, Cash Flow Hedge Adjustments	(21)
Other comprehensive income before reclassifications, Total	(4,439)
Amounts reclassified from AOCI, Foreign Currency Translation Adjustments
Amounts reclassified from AOCI, Defined Benefit Pension Plan Adjustments	863
Amounts reclassified from AOCI, Cash Flow Hedge Adjustments	9
Amounts reclassified from AOCI, Total	872
Foreign currency translation adjustments (Note 10)	(4,418)	8,459
Net current-period other comprehensive income, Defined Benefit Pension Plan Adjustments	863	582
Net current-period other comprehensive income, Cash Flow Hedge Adjustments	(12)	107
Net current-period other comprehensive income, Total	(3,567)
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Balance at March 31, 2013	(7,304)
Accumulated Other Comprehensive Income (Loss), Defined Benefit Pension Plan Adjustments, Balance at March 31, 2013	(34,635)
Accumulated Other Comprehensive Income (Loss), Cash Flow Hedge Adjustments, Balance at March 31, 2013	122
Accumulated Other Comprehensive Income (Loss), Balance at March 31, 2013	$ (41,817)