Exchange Rates Used to Translate Amounts in RMB to U.S. Dollars (Detail)	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Balance sheet items, except for equity accounts	6.2689	6.2855
Items in the statements of income and cash flows	6.2785	6.3074

Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 830

-SubTopic 30

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6897108&loc=SL6897125-166521

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant