Derivatives and Hedging Activities - Narrative (Details) lb in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2018 USD ($) lb	Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($) lb	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)
Fair value of derivatives
Total asset derivatives on a gross basis	$ 36,600,000		$ 36,600,000
Total liability derivatives on a gross basis	5,900,000		5,900,000
Cash collateral held by counterparties	$ 0		0		$ 0
Net derivative losses included in AOCI expected to be reclassified into earnings			$ 11,000,000
Cash flow hedges | Commodity contracts
Fair value of derivatives
Amounts of raw materials to be purchased from forward contracts (in pounds) | lb	20.9		20.9
Cash flow hedges | Interest Rate Swaps
Fair value of derivatives
Net gains (losses) recorded as a reduction to interest expense	$ 100,000	$ 100,000	$ 300,000	$ 300,000
Fair value hedging | Interest Rate Swaps
Fair value of derivatives
Net gains (losses) recorded as a reduction to interest expense	(100,000)	$ 400,000	400,000	$ 1,300,000
Total notional amounts of interest rate contracts	$ 150,000,000		$ 150,000,000		$ 150,000,000