Employee Benefit Plans - Multi-Employer Plan (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($) plan	Mar. 31, 2017 USD ($)	Jun. 30, 2012 USD ($) quarter	Jan. 05, 2015 USD ($)	Nov. 18, 2014 USD ($)
Multiemployer Plans [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Amount	$ 500,000	$ 400,000	$ 1,500,000	$ 1,200,000
Multiemployer plans, number of plans | plan			2
Labor Management Pension Fund
Multiemployer Plans [Line Items]
Withdrawal obligation	4,000,000		$ 4,000,000		$ 4,300,000	$ 4,900,000	$ 4,400,000
Multiemployer plan, quarterly installments for withdrawal liability					$ 91,000
Multiemployer plan, quarterly installments for withdrawal liability, number of quarters | quarter					80
Multiemployer Plans, Pension | Multiemployer Plans, Defined Benefit Pension Plans [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, number of plans | plan			2
Other Postretirement Benefit Plan
Multiemployer Plans [Line Items]
Defined Benefit Plan, Service Cost	152,000	190,000	$ 456,000	570,000
Multiemployer plans, number of plans | plan			9
Defined Benefit Plan, Interest Cost	209,000	207,000	$ 627,000	621,000
Defined Benefit Plan, Amortization of Gain (Loss)	(210,000)	(157,000)	(630,000)	(471,000)
Amortization of prior service credit	(439,000)	(439,000)	(1,317,000)	(1,317,000)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (288,000)	$ (199,000)	$ (864,000)	$ (597,000)