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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.

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Number of share options (or share units) exercised during the current period.

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Incentive Plan - Narrative (Details) - shares				9 Months Ended
Incentive Plan - Narrative (Details) - shares	May 21, 2018	Feb. 08, 2018	Mar. 15, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised (in shares)				0	0
Granted during period (in shares)				551,650
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options expiration period				10 years
Vesting period				3 years
Restricted stock awards and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	10 months
Granted during period (in shares)	48,400
Phantom Restricted Stock Awards \| March, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Shares issued (in shares)		82,170
Phantom Restricted Stock Awards \| March, 2017 \| Vesting Period One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			33.33%
Phantom Restricted Stock Awards \| March, 2017 \| Vesting Period Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			33.33%
Phantom Restricted Stock Awards \| March, 2017 \| Vesting Period Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			33.33%