Fair Value Measurements (Details) $ in Millions	3 Months Ended
Jun. 30, 2018 USD ($)
Financial Liabilities
Transfer of assets from level 1 to level 2	$ 0.0
Transfer of assets from level 2 to level 1	0.0
Transfer of liabilities from level 1 to level 2	0.0
Transfer of liabilities from level 2 to level 1	0.0
Transfer of assets into level 3	0.0
Transfer of assets out of level 3	0.0
Transfer of liabilities into level 3	0.0
Transfer of liabilities out of level 3	0.0
Recurring
Financial Assets
Total	4.1
Financial Liabilities
Long-term debt	2,144.1
Total	2,149.0
Recurring \| Interest rate swaps
Financial Assets
Financial Assets	4.1
Financial Liabilities
Financial Liabilities	4.9
Level 2 \| Recurring
Financial Assets
Total	4.1
Financial Liabilities
Long-term debt	2,144.1
Total	2,149.0
Level 2 \| Recurring \| Interest rate swaps
Financial Assets
Financial Assets	4.1
Financial Liabilities
Financial Liabilities	$ 4.9

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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