STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Sep. 30, 2019

Schedule of Employee Service Share-Based Compensation Allocation of Recognized Period Costs

	Three Months Ended September 30,
	2019		2018
	(in millions)
Included in:
Operating costs	$	3.2	$	2.7
Selling, general and administrative expenses		24.0		24.0
Total stock-based compensation expense	$	27.2	$	26.7
Part A restricted stock units	$	22.7	$	23.3
Part B restricted stock units		3.8		2.9
Part C restricted stock units		0.7		0.5
Total stock-based compensation expense	$	27.2	$	26.7

Summary of Part B RSU Issuance

	During the Three Months Ended
	September 30, 2019
Part B RSUs granted		64,705
Maximum eligible shares of the Company's common stock		446,465
Grant date fair value per Part B RSU	$	69.86
Units converted to the Company's common stock at vesting date		n/a

	During the Three Months Ended
	June 30, 2019		March 31, 2019		December 31, 2018		September 30, 2018
Part B RSUs granted		75,370		98,342		61,123		58,418
Maximum eligible shares of the Company's common stock		520,053		678,560		421,749		403,084
Grant date fair value per Part B RSU	$	63.67	$	52.81	$	22.43	$	64.41
Units converted to the Company's common stock at vesting date		n/a		n/a		n/a		—

Part A restricted stock units

Summary of Restricted Stock Units Activity

The following table summarizes the Company’s Part A RSU activity for the three months ended September 30, 2019:

	Number of Part A RSUs	Weighted average grant-date fair value per share		Weighted average remaining contractual term in months
Outstanding at July 1, 2019	2,324,396	$	28.49	6.6
Granted	640,191		33.73
Vested	(552,064)		25.93
Forfeited	(74,448)		n/a
Outstanding at September 30, 2019	2,338,075	$	30.39	5.8

Part B restricted stock units

Summary of Restricted Stock Units Activity

The following table summarizes the Company’s Part B RSU activity for the three months ended September 30, 2019:

	Number of Part B RSUs	Weighted average grant-date fair value per unit		Weighted average remaining contractual term in months
Outstanding at July 1, 2019	289,254	$	49.73	8.0
Granted	64,705		69.86
Vested	(57,336)		64.41
Forfeited	—		n/a
Outstanding at September 30, 2019	296,623	$	51.28	7.5