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	Dec. 31, 2016	Jun. 30, 2016
Carrying Value
Carrying amounts and estimated fair values of financial instruments not recorded at fair value
Long-term debt	$ 604.0	$ 611.3
Company-owned life insurance	14.6	14.0
Fair Value
Carrying amounts and estimated fair values of financial instruments not recorded at fair value
Long-term debt	596.6	597.7
Company-owned life insurance	$ 14.6	$ 14.0