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

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Percentage of vesting of award under share-based payment arrangement.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		147 Months Ended	195 Months Ended
	May 31, 2014	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2021	Dec. 31, 2020	May 20, 2020	May 19, 2020	Dec. 31, 2008	Dec. 31, 2004
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 1,008	$ 1,634
Stock-based compensation expense to be recognized through results of operations		$ 6,396		$ 6,396	$ 6,396
Employee Stock Award Plan-2008
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)		579,589		579,589	579,589	700,680			1,900,000
Additional shares authorized (in shares)	1,500,000	0		1,500,000
Employee Stock Award Plan-2008 \| Options Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period		10 years
Employee Stock Award Plan-2008 \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		20.00%
Employee Stock Award Plan-2008 \| Share-based Compensation Award, Tranche One \| Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Employee Stock Award Plan-2008 \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage		33.30%
Employee Stock Award Plan-2008 \| Share-based Compensation Award, Tranche Two \| Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years
Director Plan - 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)		162,862		162,862	162,862	160,135	450,000	300,000		300,000
Additional shares authorized (in shares)		0			150,000