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

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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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Stock-Based and Other Long-Term Incentive Compensation (Restricted Stock) (Details) - Restricted Stock - USD ($) $ in Millions		6 Months Ended
	Apr. 28, 2020	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 1.0	$ 1.1
Total unrecognized compensation expense		$ 2.9
Unrecognized compensation cost related to awards, vesting period		2 years 9 months
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	94,133
Award vesting period	3 years
Chief Financial Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	10,000
Vice President of Technical Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		4,432
Award vesting period		1 year