Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Schedule of restricted stock unit activity

	Number of Shares			Weighted Average Grant Date Fair Value Per Share
Unvested Outstanding at January 1, 2019		2,251,059		$	6.19
Granted		746,522		$	6.53
Forfeited		(13,353	)	$	(6.81	)
Vested		(1,412,264	)	$	(6.10	)
Unvested Outstanding at December 31, 2019		1,571,964		$	6.43

Schedule of stock-based compensation expense

	Year Ended December 31,		Three Months Ended December 31,		Year Ended September 30,
	2019		2018		2018
	(in millions)
RSAs and RSUs	$	8.7	$	1.6	$	5.0
Modification of awards		—		—		2.1
Payroll taxes on vesting of RSUs		0.3		—		0.3
	$	9.0	$	1.6	$	7.4