Reconciliation of Provision For Income Taxes Determined at Local Income Tax Rate to Effective Income Tax Rate (Detail) (USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Reconciliation of Effective Income Tax Rate [Line Items]
Pre-tax income	$ 23,085,469	$ 17,946,895	$ 57,134,102	$ 53,339,558
United States federal corporate income tax rate	34.00%	34.00%	34.00%	34.00%
Income tax computed at United States statutory corporate income tax rate	7,849,060	6,101,943	19,425,595	18,135,450
Loss not recognized as deferred tax assets	237,951	140,242	838,138	566,151
Change in fair value of warrants	(153,340)	(189,455)	(17,099)	(1,087,568)
Rate differential for PRC earnings	(2,103,517)	(1,593,293)	(5,370,521)	(4,649,092)
Other	28,677	(40,625)	109,673	(31,528)
Effective tax expense	$ 5,858,831	$ 4,418,812	$ 14,985,786	$ 12,933,413

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.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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- Definition

The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to changes in the valuation allowance for deferred tax assets in the period.

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- Definition

The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to total foreign income tax expense or benefit. The foreign income tax expense or benefit difference represents the income tax expense or benefit at applicable domestic statutory income tax rates applied to foreign earnings or loss for the period versus the foreign income tax expense or benefit calculated by applying the appropriate foreign tax rates.

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- Definition

The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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