Fair Value Measurement - Accumulated Derivative Instruments (Loss) Gain (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cumulative Changes in Derivative Net Gain (Loss) [Roll Forward]
Balance at beginning of period	$ (1.9)	$ (0.3)	$ 7.5
Reclassification to Earnings		(0.6)	(2.1)
Current period change in fair value	(7.3)	(1.0)	(5.7)
Balance at end of period	(10.9)	$ (1.9)	$ (0.3)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Cumulative Changes in Derivative Net Gain (Loss) [Roll Forward]
Reclassification to Earnings	$ (1.7)