Note 2 - Inventories (Detail) (Barite Ore [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Barite Ore [Member]
Increase (Decrease) in Raw Materials, Packaging Materials and Supplies Inventories	$ 20.8

The increase (decrease) during the reporting period in the value of raw materials, packaging materials and supplies held in inventory.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Name:	us-gaap_IncreaseDecreaseInRawMaterialsPackagingMaterialsAndSuppliesInventories
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration