Organization and Summary of Accounting Policies - Investments in Unconsolidated Affiliates (Details) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Aug. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) surgical_facility	Dec. 31, 2018 USD ($) surgical_facility
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Current assets			$ 51.8	$ 41.2
Noncurrent assets			47.4	27.8
Current liabilities			25.5	21.8
Noncurrent liabilities			5.8	3.8
Income Statement
Net revenues			188.5	169.8
Cost of revenues			132.0	118.5
Net income			$ 51.1	48.2
Number of surgical facilities acquired | surgical_facility			4
Purchase of equity investments	$ 0.0	$ 0.0	$ (15.2)	$ 0.0
Number of surgery facilities sold | surgical_facility				1
Proceeds from sale of equity method investments				$ 0.5
Gain (loss) deconsolidation				1.1
Fair value				$ 2.0