XML 122 R101.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Commitments and contingencies - Matters relating to the St. Croix Alumina Refining Facility (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2015 USD ($)
Accrual for Environmental Loss Contingencies [Abstract] |
Environmental remediation expense for Hydrocarbon Recovery Plan | $ 1,085

X
- References No definition available. + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingenciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13296-110859 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 + Details
Name: | us-gaap_EnvironmentalRemediationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration