Income tax and deferred taxes (Details 5) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Income tax and deferred taxes [Line Items]
Net operating loss carryforwards	$ 1,437	$ 1,302
CHILE [Member]
Disclosure of Income tax and deferred taxes [Line Items]
Net operating loss carryforwards	$ 1,437	$ 1,302

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

No definition available.

Name:	sqm_NetOperatingLossCarryforwards
Namespace Prefix:	sqm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant