Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Changes In Equity [Abstract]
Dividends declared and paid, per share	$ 7.62	$ 5.72	$ 4.07
Capital distribution, per share	$ 2.38	$ 3.33	$ 3.33

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 107
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_107&doctype=Standard
-URIDate 2018-03-16

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