Employee Benefit Plans - Multi-Employer Plan (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2019 USD ($) hour plan	Mar. 31, 2018 USD ($)	Jun. 30, 2012 USD ($) quarter	Jun. 30, 2018 USD ($)	Jan. 05, 2015 USD ($)	Nov. 18, 2014 USD ($)
Multiemployer Plans [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Amount	$ 700,000	$ 500,000	$ 1,600,000	$ 1,500,000
Multiemployer plans, number of plans | plan			2
Defined contribution plan, hours threshold for eligibility | hour			1,000
Defined contribution plan, employer matching contribution percent	100.00%		50.00%
Defined contribution plan, employer matching contribution, percent of eligible income	4.00%		6.00%
Defined contribution plan, employer matching contribution, annual vesting percent			20.00%
WCTPP [Member]
Multiemployer Plans [Line Items]
Withdrawal obligation	$ 2,100,000		$ 2,100,000
Labor Management Pension Fund
Multiemployer Plans [Line Items]
Withdrawal obligation					$ 4,300,000	$ 3,800,000	$ 4,900,000	$ 4,400,000
Multiemployer plan, quarterly installments for withdrawal liability					$ 100,000
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
Pension Plan
Multiemployer Plans [Line Items]
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	1,126,000	1,456,000	$ 4,096,000	4,368,000
Defined Benefit Plan, Service Cost	0	0	0	0
Defined Benefit Plan, Interest Cost	1,173,000	1,432,000	4,025,000	4,296,000
Defined Benefit Plan, Amortization of Gain (Loss)	380,000	418,000	1,120,000	1,254,000
Net periodic benefit (credit) cost	427,000	394,000	$ 11,997,000	1,182,000
Other Postretirement Benefit Plan
Multiemployer Plans [Line Items]
Multiemployer plans, number of plans | plan			9
Defined Benefit Plan, Service Cost	133,000	152,000	$ 399,000,000	456,000,000
Defined Benefit Plan, Interest Cost	222,000	209,000	666,000,000	627,000,000
Defined Benefit Plan, Amortization of Gain (Loss)	(209,000)	(210,000)	(627,000,000)	(630,000,000)
Amortization of prior service credit	(439,000)	(439,000)	(1,317,000,000)	(1,317,000,000)
Net periodic benefit (credit) cost	$ (293,000)	$ (288,000)	(879,000,000)	$ (864,000,000)
Employee-related | WCTPP [Member]
Multiemployer Plans [Line Items]
Multiemployer plan, quarterly installments for withdrawal liability			$ 190,507