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Employee Benefit Plans Narrative (Details)
3 Months Ended 12 Months Ended
Sep. 30, 2018
USD ($)
quarter
hour
plan
Jun. 30, 2012
USD ($)
quarter
Jun. 30, 2018
USD ($)
Jan. 05, 2015
USD ($)
Nov. 18, 2014
USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Multiemployer plans, number of plans | plan 2        
Defined contribution plan, hours threshold for eligibility | hour 1,000        
Defined contribution plan, employer matching contribution percent 50.00%        
Defined contribution plan, employer matching contribution, percent of eligible income 6.00%        
Defined contribution plan, employer matching contribution, annual vesting percent 20.00%        
Defined contribution plan, vesting period 5 years        
Defined contribution plan, automatic vesting age 65 years        
Defined contribution plan, employee vesting percent 100.00%        
Defined Contribution Plan, Employer Matching Contribution, Amount $ 500,000        
Minimum          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Investment horizon for long-term capital market assumptions 20 years        
Maximum          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Investment horizon for long-term capital market assumptions 30 years        
WCTPP [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Multiemployer Plans, Withdrawal Obligation, Assessment $ 3,400,000        
Multiemployer plan, quarterly installments for withdrawal liability, number of quarters | quarter 18        
Labor Management Pension Fund          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Withdrawal obligation $ 3,000,000 $ 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      
Other Postretirement Benefit Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Multiemployer plans, number of plans | plan 9        
Multiemployer Plans, Pension | Multiemployer Plans, Defined Benefit Pension Plans [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Multiemployer plans, number of plans | plan 2        
Multiemployer Plans, Pension | Multiemployer Plans, Defined Contribution Pension Plan [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Multiemployer plans, number of plans | plan 1        
Employee-related | WCTPP [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Withdrawal obligation $ 3,200,000        
Multiemployer plan, quarterly installments for withdrawal liability $ 190,507