Acquisitions - Other Acquisitions (Details) $ in Millions	3 Months Ended						12 Months Ended
	Jun. 30, 2019 item	Mar. 31, 2019 item	Sep. 30, 2018 item	Jun. 30, 2018 item	Mar. 31, 2018 item	Jun. 30, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) item
Acquisitions
Number of acquisitions | item	1	1	2	3	2				4
Total purchase price							$ 2.6	$ 96.4	$ 9.4
Number of acquisitions reported as separate operating location | item			1
BCH
Acquisitions
Total purchase price						$ 121.3
Amount allocated to goodwill and intangible assets for acquisitions						97.0
Purchase price paid in cash						95.4
Promissory note payable						14.3
Contingent earn-out obligation						$ 11.6