Employee Benefit Plans - Multi-Employer Plan (Details)	3 Months Ended
	Sep. 30, 2019 USD ($) plan	Sep. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)
Multiemployer Plans [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Amount	$ 700,000	$ 500,000
Local 807 Pension Plan [Member]
Multiemployer Plans [Line Items]
Other Commitment, Due after Fifth Year	182,000
Pension Plan
Multiemployer Plans [Line Items]
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	1,102,000	1,485,000
Defined Benefit Plan, Service Cost	0	0
Defined Benefit Plan, Interest Cost	1,059,000	1,426,000
Defined Benefit Plan, Amortization of Gain (Loss)	370,000	370,000
Net periodic benefit (credit) cost	$ 327,000	311,000
Other Postretirement Benefit Plan
Multiemployer Plans [Line Items]
Multiemployer plans, number of plans | plan	9
Defined Benefit Plan, Service Cost	$ 147,000	133,000
Defined Benefit Plan, Interest Cost	214,000	222,000
Defined Benefit Plan, Amortization of Gain (Loss)	(125,000)	(209,000)
Amortization of prior service credit	(392,000)	(439,000)
Net periodic benefit (credit) cost	(156,000)	(293,000)
Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	428,000	$ 495,000
Multiemployer Plans, Pension | WCT Pension Trust [Member]
Multiemployer Plans [Line Items]
Other Commitment, Due after Fifth Year	916,000		$ 1,487,000
Multiemployer Plans, Pension | Local 807 Pension Plan [Member]
Multiemployer Plans [Line Items]
Other Commitment, Due after Fifth Year	182,000
Multiemployer plan, quarterly installments for withdrawal liability	91,000
Defined Benefit Plan, Benefit Obligation, Payment for Settlement	3,000,000
Multiemployer Plans, Pension | WCTPP [Member]
Multiemployer Plans [Line Items]
Multiemployer Plans, Withdrawal Obligation, Assessment	3,400,000
Multiemployer Plans, Pension | Employee-related | WCTPP [Member]
Multiemployer Plans [Line Items]
Multiemployer plan, quarterly installments for withdrawal liability	190,507
Defined Benefit Plan, Benefit Obligation, Payment for Settlement	$ 153,822