Equity - Additional Information (Detail) ADSs in Millions	12 Months Ended
Dec. 31, 2017 ADSs $ / shares shares
Disclosure of classes of share capital [Line Items]
Common stock par value \| $ / shares	$ 10
Percentage of American Depositary Shares as common stock outstanding	3.36%
Percentage of net income allocation toward legal reserve	10.00%
Bottom of range [Member]
Disclosure of classes of share capital [Line Items]
Percentage of retained earnings distributed as dividend	50.00%
Dividend distributed per share threshold in the form of common stocks \| $ / shares	$ 0.10
Percentage of legal reserve on additional paid in capital	25.00%
American Depositary Shares [Member]
Disclosure of classes of share capital [Line Items]
Number of common stocks represented by 1 ADS \| shares	10
Number of common stock outstanding \| shares	261
Number of units \| ADSs	26

Number of common shares for each American depository share.

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- Definition

Number of units.

+ References

No definition available.

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- Definition

Percentage of American Depositary Shares as common stock outstanding.

+ References

No definition available.

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- Definition

Percentage of legal reserves on additional paid in capital.

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No definition available.

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- Definition

Percentage of net income allocation toward legal reserve.

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No definition available.

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- Definition

Percentage of retained earnings distributed as dividend.

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No definition available.

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

+ References

No definition available.

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- Definition

The amount, per share, of dividends recognised as distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The number of shares that have been authorised and issued, reduced by treasury shares held. [Refer: Treasury shares]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The nominal value per share.

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