XML 159 R144.htm IDEA: XBRL DOCUMENT v2.4.0.8

Geographical and Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013 Facility
Segment Reporting Information [Line Items]
Number of mines newly acquired	2

X

- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfBusinessesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration