Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	$ 20.9	$ 18.4	$ 11.6
Cash paid for income taxes	$ 40.9	$ 78.1	$ 123.2