Segment and Geographic Information - Identifiable Assets (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Identifiable assets:
Total	$ 1,982.1	$ 1,954.7
United States
Identifiable assets:
Total	1,808.1	1,781.0
Canada
Identifiable assets:
Total	$ 174.0	$ 173.7