Inventories - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2017
Inventory Disclosure [Abstract]
Reduction to net loss resulting from effect of LIFO inventory liquidation	$ 0.0	$ 0.8	$ 2.5