Employee Benefit Plans - Multi-Employer Plan (Details)	12 Months Ended
	Jun. 30, 2018 USD ($) plan	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2015 quarter	Jan. 05, 2015 USD ($)	Nov. 18, 2014 USD ($)	Jun. 30, 2012 USD ($)
Multiemployer Plans [Line Items]
Defined contribution plan, employer matching contribution	$ 2,000,000	$ 1,600,000	$ 1,600,000
Multiemployer plan, unfunded benefit liability				$ 3,300,000
Withdrawal obligation	3,800,000
Multiemployer plan, period contribution	4,800,000	$ 5,300,000	$ 6,300,000
Multiemployer plan, estimated contribution in next fiscal year	$ 5,100,000
Western Conference of Teamsters Pension Plan
Multiemployer Plans [Line Items]
Funded status of multiemployer plans	92.00%	91.20%	91.70%
Employer contributions	$ 1,605,000	$ 2,114,000	$ 2,587,000
Employer contributions (percentage)		5.00%
Labor Management Pension Fund
Multiemployer Plans [Line Items]
Withdrawal obligation	3,800,000					$ 4,900,000	$ 4,400,000	$ 4,300,000
Multiemployer plan, quarterly installments for withdrawal liability	91,000		100,000
Multiemployer plan, quarterly installments for withdrawal liability, number of quarters | quarter					80
Program for Enhanced Early Retirement
Multiemployer Plans [Line Items]
Employer contributions (percentage)		6.50%
Employer contributions (hours)		173
All Other Plans
Multiemployer Plans [Line Items]
Employer contributions	35,000	$ 39,000	$ 39,000
Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Multiemployer plan, estimated contribution in next fiscal year	$ 1,700,000
Other Postretirement Benefits Plan
Multiemployer Plans [Line Items]
Multiemployer plans, number of plans | plan	9
Employer contributions	$ 771,000	$ 399,000
Multiemployer Plans, Defined Benefit Pension Plans [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, number of plans | plan	2