Stock-based Payments - Summary of RSU Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	$ 43.9	$ 63.4	$ 27.1
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	45.7	64.7	29.6
Unrecognized compensation expense related to RSUs	58.0
Time-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	43.4	43.8	20.0
Unrecognized compensation expense related to RSUs	$ 53.0
Weighted average period	1 year 10 months 24 days
Co-Investment RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	$ 0.4	0.6	1.5
Unrecognized compensation expense related to RSUs	0.1
Performance-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	1.9	15.4	0.0
Unrecognized compensation expense related to RSUs	4.9
Restricted Stock Units (RSUs), Equity Classification
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	45.7	59.8	21.5
Unrecognized compensation expense related to RSUs	58.0
Restricted Stock Units (RSUs), Liability Classification
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO stock-based compensation	0.0	$ 4.9	$ 8.1
Unrecognized compensation expense related to RSUs	$ 0.0

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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