Stock-Based Compensation - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	$ (1.2)	$ 1.3
Stock-based compensation liability	0.1
Unrecognized compensation expense	$ 0.4
Unrecognized stock-based compensation cost, recognition period	1 year 7 months 6 days
Vested in period, fair value	$ 0.1
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	$ (0.5)	$ (0.3)
Unrecognized stock-based compensation cost, recognition period	9 months 18 days

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

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Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements.

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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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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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