Consolidated Statement of Changes in Members' Equity (Parenthetical) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020		Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Stockholders' Equity [Abstract]
Income tax (benefit) expense	$ 1.1	[1]	$ 0.5	$ (4.0)	$ (0.5)	$ (3.6)	$ (2.4)	$ (4.1)

[1] Includes a tax expense of $1.1 million and a tax benefit of $2.4 million for the three and nine months ended September 30, 2020, respectively, and a tax benefit of $0.5 million and $4.1 million for the three and nine months ended September 30, 2019, respectively.