Investment in ARMA Energy, Inc - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 28, 2013
Variable Interest Entities Not Consolidated [Line Items]
Investment in unconsolidated entity	$ 0
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member]
Variable Interest Entities Not Consolidated [Line Items]
Preferred stock received	71.00%
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] \| Promissory Note [Member]
Variable Interest Entities Not Consolidated [Line Items]
Promissory note, Principal amount	500
Promissory note, Maturity period	5 years
Annual principal payment	$ 100

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant