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 9 Months Ended
Mar. 31, 2018
USD ($)
Mar. 31, 2017
USD ($)
Mar. 31, 2018
USD ($)
Installment
Mar. 31, 2017
USD ($)
Cash Long-Term Incentive Plan        
Cash-based long-term incentive plan, granted amount     $ 5.9 $ 51.6
Cash long-term incentive plan, compensation expense $ 11.6 $ 11.3 37.9 $ 34.7
Cash long-term incentive plan, unrecognized compensation balance $ 91.4   $ 91.4  
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