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Significant Accounting Policies - Summary of Maximum Average Useful Lives of Fixed Assets (Detail)	12 Months Ended
	Dec. 31, 2017
Administrative Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Years	35 years
Industrial Buildings [member]
Disclosure of detailed information about property, plant and equipment [line items]
Years	30 years
Machinery and Equipment in Plant [member]
Disclosure of detailed information about property, plant and equipment [line items]
Years	17 years
Ready-mix Trucks and Motor Vehicles [member]
Disclosure of detailed information about property, plant and equipment [line items]
Years	9 years
Office Equipment and Other Assets [member]
Disclosure of detailed information about property, plant and equipment [line items]
Years	6 years