Stock-Based Compensation - Compensation Expense (Income) Recorded for All Stock Options, Stock Awards and SARs (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Compensation expense (income)	$ 3,607	$ (201)	$ 8,055	$ 2,961

Allocated share based compensation expense (income).

No definition available.

Name:	scl_AllocatedShareBasedCompensationExpenseIncome
Namespace Prefix:	scl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration