Related party transactions - Additional Information (Detail) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Feb. 27, 2013	Feb. 24, 2011
Related Party Transaction [Line Items]
Borrowed from related parties	$ 840,041	$ 1,616,429		$ 793,500
Borrowed from shareholder - Short term	2,679,945	2,679,945
Related party transaction, date of maturity	Oct. 31, 2013	Oct. 31, 2013
Related party transaction, interest rate	4.4075%
Principal and interest due period	The principal and interest was required to be paid on specified due dates beginning on February 16, 2012 through October 31, 2012.
Related Party Offset Amount			0
Mr. Rongxiu Xiang
Related Party Transaction [Line Items]
Borrowed from shareholder - Short term	$ 840,041

Amounts due to recorded owners or owners with a beneficial interest of more than 10 percent of the voting interests or officers of the company. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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China Natural Gas, Inc. 10-Q