Fair Value Measurements - Schedule of carrying amounts and estimated fair values of financial instruments not recorded at fair value in the financial statements (Details) - Level 2 - USD ($) $ in Millions	Mar. 31, 2017	Jun. 30, 2016
Carrying Value
Carrying amounts and estimated fair values of financial instruments not recorded at fair value
Long-term debt	$ 604.1	$ 611.3
Company-owned life insurance	15.6	14.0
Fair Value
Carrying amounts and estimated fair values of financial instruments not recorded at fair value
Long-term debt	622.7	597.7
Company-owned life insurance	$ 15.6	$ 14.0