Date the declared dividend will be paid, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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The per share amount of a dividend declared, but not paid, as of the financial reporting date.

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The percentage rate used to calculate dividend payments on preferred stock.

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Earnings per Ordinary Share - Summary of Declared Dividends (Details) - $ / shares			3 Months Ended	12 Months Ended
	Apr. 26, 2017	Sep. 20, 2016	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
7.250% preference shares
Dividends Payable [Line Items]
Preference shares, rate			7.25%	7.25%
5.95% preference shares
Dividends Payable [Line Items]
Preference shares, rate			5.95%		5.95%
5.625% preference shares
Dividends Payable [Line Items]
Preference shares, rate		5.625%	5.625%	5.625%
Subsequent Event \| Ordinary shares
Dividends Payable [Line Items]
Dividend (in usd per share)	$ 0.24
Payable Date	May 30, 2017
Record Date	May 12, 2017
Subsequent Event \| 7.250% preference shares
Dividends Payable [Line Items]
Dividend (in usd per share)	$ 0.4531
Payable Date	Jul. 01, 2017
Record Date	Jun. 15, 2017
Subsequent Event \| 5.95% preference shares
Dividends Payable [Line Items]
Dividend (in usd per share)	$ 0.3719
Payable Date	Jul. 01, 2017
Record Date	Jun. 15, 2017
Subsequent Event \| 5.625% preference shares
Dividends Payable [Line Items]
Dividend (in usd per share)	$ 0.35156
Payable Date	Jul. 01, 2017
Record Date	Jun. 15, 2017