Income Taxes (Details 2)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of statutory rates to Company's effective tax rate
PRC Statutory rate	25.00%	25.00%	25.00%
Effect of different tax jurisdiction	(0.60%)	(0.60%)	(1.00%)
Effect of expenses not deductible for PRC tax purposes		0.10%	0.10%
Effect of income not taxable for PRC tax purposes	0.30%	(0.30%)
Under provision in previous year		0.10%	0.10%
Change in valuation allowance	2.40%	2.20%	3.50%
Effective income tax rate	27.10%	26.50%	27.70%

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 2

-Article 4

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(2))

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- Definition

The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 47

-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 740

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319

Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

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-Subparagraph (SAB TOPIC 6.I)

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to changes in the valuation allowance for deferred tax assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the difference between statutory income tax rates in foreign jurisdictions and the domestic federal statutory income tax rate recorded during the period.

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The sum of the differences between the effective income tax rate and domestic federal statutory income tax rate attributable to all nondeductible expenses under enacted tax laws.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to revisions in previously reported amounts of income tax provision.

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The portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to income that is exempt from income taxes under enacted tax laws.

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