Consolidated Statements of Comprehensive Loss - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (43.6)	$ (55.1)	$ (103.8)
Cash flow hedges:
Cash flow hedge gain	0.2	0.0	0.0
Defined benefit pension and retiree health benefit plans	(3.3)	(1.5)	1.1
Foreign currency transaction adjustment	1.2	0.0	0.0
Total other comprehensive income (loss)	(1.9)	(1.5)	1.1
Comprehensive loss attributable to partners’ capital	$ (45.5)	$ (56.6)	$ (102.7)