Share-Based Compensation - Other Than Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019
RSAs
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding and unvested at beginning of period (in shares)	0
Granted (in shares)	0
Vested (in shares)	0
Forfeited (in shares)	0
Outstanding and unvested at end of period (in shares)	0
Weighted- Average Grant Date Fair Value
Shares surrendered for taxes (in shares)	0	380,564
Cost of shares surrendered for taxes	$ 0.0	$ 3.7
RSUs
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding and unvested at beginning of period (in shares)	1,373,356
Granted (in shares)	1,443,143
Vested (in shares)	(464,758)
Forfeited (in shares)	(57,467)
Outstanding and unvested at end of period (in shares)	2,294,274
Weighted- Average Grant Date Fair Value
Outstanding and unvested at beginning of period (in dollars per share)	$ 8.03
Granted (in dollars per share)	9.87
Vested (in dollars per share)	6.50
Forfeited (in dollars per share)	6.46
Outstanding and unvested at end of period (in dollars per share)	$ 9.54
Shares surrendered for taxes (in shares)	128,906	106,173
Cost of shares surrendered for taxes	$ 1.1	$ 1.0
PBRSUs
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding and unvested at beginning of period (in shares)	4,119,436
Granted (in shares)	203,874
Vested (in shares)	0
Forfeited (in shares)	(181,543)
Outstanding and unvested at end of period (in shares)	4,141,767
Weighted- Average Grant Date Fair Value
Outstanding and unvested at beginning of period (in dollars per share)	$ 6.37
Granted (in dollars per share)	9.81
Vested (in dollars per share)	0
Forfeited (in dollars per share)	5.73
Outstanding and unvested at end of period (in dollars per share)	$ 6.57
Shares surrendered for taxes (in shares)	0	0
Cost of shares surrendered for taxes	$ 0.0	$ 0.0

Amount of decrease to equity for grantee's tax withholding obligation for award under share-based payment arrangement.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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-Publisher FASB
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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Name Accounting Standards Codification
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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

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No definition available.

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