Capital (Details) $ / shares in Units, $ in Millions |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
|
Mar. 15, 2019
USD ($)
$ / shares
|
Mar. 16, 2018
USD ($)
$ / shares
|
Sep. 30, 2019
$ / shares
|
Sep. 30, 2018
$ / shares
|
Sep. 30, 2019
$ / shares
shares
|
Sep. 30, 2018
$ / shares
shares
|
|
| Class of Stock [Line Items] | ||||||
| Payments of dividends | $ | $ 46.5 | $ 31.7 | ||||
| Dividend paid per sub-share (in dollars per share) | $ 0 | $ 0 | $ 6.00 | $ 4.05 | ||
| Sub Shares | ||||||
| Class of Stock [Line Items] | ||||||
| Ratio of certificates to sub-shares | 0.00033333 | |||||
| Number of shares repurchased and retired (in shares) | shares | 6,258 | 39,768 | ||||
| Cash Dividend | Sub Shares | ||||||
| Class of Stock [Line Items] | ||||||
| Dividend paid per sub-share (in dollars per share) | $ 1.75 | $ 1.05 | ||||
| Special Dividend | Sub Shares | ||||||
| Class of Stock [Line Items] | ||||||
| Dividend paid per sub-share (in dollars per share) | $ 4.25 | $ 3.00 | ||||
| X | ||||||||||
- Definition Sub-share Certificate Equivalent Ratio No definition available.
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- Definition 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. No definition available.
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- Definition Aggregate dividends paid during the period for each share of common stock outstanding. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Number of shares that have been repurchased and retired during the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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