Share Capital, Option Plans and Share-Based Payments - RSU's, DSU's and ESPP (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	0	1,496	0	4,464
Award vesting period			3 years
Stock issued	$ 0.2	$ 1.4	$ 0.3	$ 1.6
Stock issued (in shares)	5,826	66,460	8,794	74,792
Deferred Stock Units (DSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	90,184	77,606	93,342	80,809
Employee Share Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards purchase price discount			15.00%
Common shares eligible for issuance (in shares)	160,088	146,248	336,162	338,617
Cash received from employee stock purchase plan	$ 4.4	$ 4.4	$ 10.1	$ 10.1

Cash collected to be used to purchase Common Stock in future periods

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price Discount

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Share-based Compensation Arrangement by Share-based Payment Award, Shares Eligible for Issuance

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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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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).

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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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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Aggregate value of stock related to Restricted Stock Awards issued during the period.

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