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

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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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Stock-Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based Compensation Expense	$ 0.2	$ 0.1
Time-based restricted stock unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based Compensation Expense	0.8	0.1	$ 1.6
Associated tax benefit from stock-based compensation expense	0.4
Unrecognized compensation expense	5.0		$ 5.0
Period for unrecognized compensation expense expected to be recognized			3 years 21 days
Time-based stock option awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based Compensation Expense			$ 0.3	$ 0.1
Associated tax benefit from stock-based compensation expense	0.1	$ 0.1	0.1	$ 0.1
Unrecognized compensation expense	$ 2.7		$ 2.7
Period for unrecognized compensation expense expected to be recognized			3 years 5 months 8 days
Maximum \| Time-based restricted stock unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Associated tax benefit from stock-based compensation expense			$ 0.4