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
Sep. 30, 2017
USD ($)
Installment
Sep. 30, 2016
USD ($)
Cash Long-Term Incentive Plan    
Cash-based long-term incentive plan, granted amount $ 2.1 $ 1.6
Cash long-term incentive plan, compensation expense 14.8 $ 12.2
Cash long-term incentive plan, unrecognized compensation balance $ 113.4  
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