Stock-Based Compensation - Compensation Expense Recorded for All Stock Options, Stock Awards and SARs (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Compensation expense	$ 1,385	$ 2,423

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