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Basis of Preparation - Narrative (Details) - Accounting Standards Update 2016-09 - USD ($) $ in Millions	Mar. 31, 2017		Mar. 31, 2016
Retained earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption	$ 2.8	[1]	$ 0.0
Additional paid-in capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption	$ 7.9
[1] The $2.8 million relates to the cumulative effect-adjustment to opening retained earnings as a result of the classification of restricted share units as equity following the adoption of ASU 2016-09

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