No definition available.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Period Type:	duration

- Definition

Net number of share options (or share units) granted during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount remaining of a stock repurchase plan authorized.

+ References

No definition available.

+ Details

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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Balance Type:	debit
Period Type:	duration

- Definition

The percentage of the original award that is paid out to employees at the end of the vesting period.

+ References

No definition available.

+ Details

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- Definition

Value of aggregate grant date fair value during the period.

+ References

No definition available.

+ Details

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- Definition

The maximum potential share payout at each balance sheet date.

+ References

No definition available.

+ Details

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- Definition

-- None. No documentation exists for this element. --

+ References

No definition available.

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- Details

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Share Capital - Narrative (Details) - USD ($)	3 Months Ended
Share Capital - Narrative (Details) - USD ($)	Mar. 31, 2018	Feb. 17, 2017
Minimum
Stock plans
Award vesting period	3 years
Maximum
Stock plans
Award vesting period	4 years
Stock options
Stock plans
Options granted (in shares)	400,000
Options, weighted average grant date fair value, per share	$ 10.34
Restricted Stock [Member]
Stock plans
Other awards granted during the period (in shares)	870
Aggregate grant date fair value	$ 37,514
Restricted stock units
Stock plans
Other awards granted during the period (in shares)	1,200,000
Aggregate grant date fair value	$ 50,900,000
Restricted stock units \| Three Year Option
Stock plans
Award vesting period	3 years
Restricted stock units \| Four Year Option
Stock plans
Award vesting period	4 years
Performance Shares
Stock plans
Other awards granted during the period (in shares)	300,000
Aggregate grant date fair value	$ 13,500,000
Maximum number of performance shares	600,000
Performance Shares \| Minimum
Stock plans
Pinal payout percentage	0.00%
Performance Shares \| Maximum
Stock plans
Pinal payout percentage	200.00%
February 2017 Program
Shareholders Equity Disclosure [Line Items]
Share repurchase program, authorized amount		$ 1,000,000,000
Share repurchase program, remaining authorization	$ 529,100,000
Settling of employee withholding taxes
Shareholders Equity Disclosure [Line Items]
Share repurchase program, value of shares repurchased and retired during the period	$ 1,700,000