Stock-based Compensation Plans and Awards - Restricted Stock Units - Additional Information (Details) - Restricted stock units (RSUs) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Stock-based Compensation
Total fair value of restricted stock vested	$ 8.3	$ 8.3
Unrecognized compensation cost related to non-vested RSUs and restricted shares	$ 14.5
Unrecognized stock-based compensation expense, weighted average period of recognition	2 years

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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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- Definition

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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-Name Accounting Standards Codification
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-Section 50
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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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