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Retirement Employee Benefits - Additional Information (Detail) - MXN ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure Of Defined Benefit Plans [Line Items]      
Employer contribution percentage 2.00%    
Defined contribution plan expense $ 6,001 $ 4,986 $ 4,728
Interest rate curve of government bonds tenure 30 years    
Average life expectancy 65 years    
Male average life expectancy 17 years    
Female average life expectancy 19 years    
Discount Rate Assumption [Member]      
Disclosure Of Defined Benefit Plans [Line Items]      
Increase decrease in basis points 1.00%    
Liability for retirement impacted $ 11,820