Stockholders' Equity - eXponential Stock Performance Plan (Details) $ in Millions				1 Months Ended	12 Months Ended			24 Months Ended	31 Months Ended
	Feb. 12, 2019 USD ($) tranche item	Jan. 02, 2019	May 24, 2018 USD ($)	Jan. 31, 2019 shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 shares	Dec. 31, 2018 shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2020 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares authorized (in shares) | shares					0	0	0
First tranche			$ 2,500.0
Market capitalization goal increment			$ 1,000.0
Recorded share-based compensation expense									$ 93.8
Number of options expected to vest | shares					5,300,000			5,300,000	5,300,000
eXponential Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, granted (in shares) | shares				60
Recorded share-based compensation expense					$ 40.8
eXponential Stock Units | 2019 eXponential Stock Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	9 years
Number of vesting tranches of share-based awards | tranche	12
Performance shares authorized (in shares) | shares					300,000
First tranche	$ 2,500.0
Number of performance goals, revenue | item	8
Number of performance goals, adjusted EBITDA | item	8
Market capitalization goal increment	$ 1,000.0
Anti-dilution provision, maximum shares growth rate per year		3.00%
Unrecognized share-based compensation cost related to unvested stock option awards, probable of achievement					$ 121.3			$ 121.3	$ 121.3
Weighted average period over which costs are recognized					4 years 7 months 28 days
Unrecognized share-based compensation cost related to unvested stock option awards, not probable of achievement					$ 11.3			$ 11.3	$ 11.3
eXponential Stock Units | 2019 eXponential Stock Performance Plan | Attained Operational Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options expected to vest | shares					400,000			400,000	400,000
eXponential Stock Units | 2019 eXponential Stock Performance Plan | Ten Operational Goals
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recorded share-based compensation expense								$ 58.3
Number of options expected to vest | shares					4,500,000			4,500,000	4,500,000