Stock Incentive Plans - Additional Disclosures (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($) compensation_plan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of active equity compensation plans \| compensation_plan	1
Recognized share-based compensation expense	$ 21.7	$ 13.8	$ 8.9
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock unit vesting period (in years)	3 years
Unrecognized compensation expense	$ 31.0
Unrecognized compensation expense, weighted average recognition period (in years)	2 years
Aggregate fair value of awards vested	$ 11.1	$ 13.7	$ 23.2

Share-based Compensation Arrangement by Share-based Payment Award, Number of Plans

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

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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