Labor obligations - Sensitivity analysis (Details) - MXN ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Average duration period of the benefit obligation	11 years 9 months 11 days	13 years 11 months 19 days	16 years 9 months
Actuarial assumption of discount rates
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase in actuarial assumption (as a percent)	1.00%
Decrease in actuarial assumption (as a percent)	100.00%
Increase in benefit obligation	$ 10,053
Decrease in benefit obligation	$ 17,706
Actuarial assumption of expected rates of salary increases
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase in actuarial assumption (as a percent)	1.00%
Decrease in actuarial assumption (as a percent)	1.00%
Increase in benefit obligation	$ 15,962
Decrease in benefit obligation	$ 16,177