Financial Risk Management - Interest Rates Used by the Group for the Fair Value Measurement (Detail)	12 Months Ended
	Dec. 31, 2018
Derivatives hedging instrument [member] | Bottom of range [member]
Disclosure of detailed information about financial instruments [Line items]
Interest rate	1.63%
Derivatives hedging instrument [member] | Top of range [member]
Disclosure of detailed information about financial instruments [Line items]
Interest rate	3.12%
Borrowings and debentures [member] | Bottom of range [member]
Disclosure of detailed information about financial instruments [Line items]
Interest rate	2.17%
Borrowings and debentures [member] | Top of range [member]
Disclosure of detailed information about financial instruments [Line items]
Interest rate	2.28%
Long-term payables - other [member] | Bottom of range [member]
Disclosure of detailed information about financial instruments [Line items]
Interest rate	2.07%
Long-term payables - other [member] | Top of range [member]
Disclosure of detailed information about financial instruments [Line items]
Interest rate	2.28%