Inventory - Additional Information (Detail) (Other Noncurrent Assets, USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Other Noncurrent Assets
Inventory [Line Items]
Inventory classified as non-current	$ 5.6	$ 5.9

Inventories not expected to be converted to cash, sold or exchanged within the normal operating cycle.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(d))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph d

-Article 5

Name:	us-gaap_InventoryNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant