Derivatives and Hedging Activities - Narrative (Details) lb in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2017 USD ($) lb	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) lb	Dec. 31, 2016 USD ($)	Jun. 30, 2017 USD ($)
Fair value of derivatives
Total asset derivatives on a gross basis	$ 33,600,000		$ 33,600,000
Total liability derivatives on a gross basis	6,000,000		6,000,000
Cash collateral held by counterparties	$ 0		0		$ 0
Net derivative losses included in AOCI expected to be reclassified into earnings			$ 10,500,000
Cash flow hedges | Commodity contracts
Fair value of derivatives
Amounts of raw materials to be purchased from forward contracts (in pounds) | lb	21.0		21.0
Cash flow hedges | Interest Rate Swaps
Fair value of derivatives
Net gains recorded as a reduction to interest expense	$ 100,000	$ 100,000	$ 200,000	$ 200,000
Fair value hedging | Interest Rate Swaps
Fair value of derivatives
Net gains recorded as a reduction to interest expense	200,000	$ 500,000	400,000	$ 900,000
Total notional amounts of interest rate contracts	$ 150,000,000		$ 150,000,000		$ 150,000,000