Quarterly report pursuant to Section 13 or 15(d)

Equity and Long-Term Incentive Compensation Plans - Cash-Based Long-Term Incentive Compensation (Details)

v3.8.0.1
Equity and Long-Term Incentive Compensation Plans - Cash-Based Long-Term Incentive Compensation (Details) - Cash long-term incentive plan
$ in Millions
 3 Months Ended 6 Months Ended
Dec. 31, 2017
USD ($)
Installment
Dec. 31, 2016
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Cash Long-Term Incentive Plan        
Cash-based long-term incentive plan, granted amount     $ 4.0 $ 50.3
Cash long-term incentive plan, compensation expense $ 11.5 $ 11.2 26.3 $ 23.4
Cash long-term incentive plan, unrecognized compensation balance $ 102.4   $ 102.4  
Minimum        
Cash Long-Term Incentive Plan        
Cash long-term incentive plan, equal vesting installments | Installment 3      
Cash long-term incentive plan, percentage of equal vesting installments     33.33%  
Cash long-term incentive plan, vesting period 3 years      
Maximum        
Cash Long-Term Incentive Plan        
Cash long-term incentive plan, equal vesting installments | Installment 4      
Cash long-term incentive plan, percentage of equal vesting installments     25.00%  
Cash long-term incentive plan, vesting period 4 years