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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Number of shares authorized for issuance under share-based payment arrangement.

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Stock-based Compensation (Details) - USD ($) shares in Thousands, $ in Thousands	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]
Compensation expense	$ 3,660	$ 4,457	$ 7,029	$ 8,945
Unrecognized compensation expense related to unvested stock-settled awards	31,132		$ 31,132
Weighted average period over which unrecognized compensation expense is expected to be recognized (in years)			3 years
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	0	0	$ 0	6
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	3,313	3,110	6,532	5,517
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	9	9	17	19
Cash-settled performance units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 338	$ 1,338	$ 480	$ 3,403
Long-Term Incentive Plan 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan	2,550		2,550