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

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Number of options outstanding, including both vested and non-vested options.

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Share-Based Compensation (Stock Options) (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period, number of years			10 years
Compensation expense	$ 1,500,000	$ 1,400,000	$ 2,400,000	$ 2,200,000
Stock options granted			55,000
Stock options exercised			27,500
Stock options forfeited			24,000
Stock options outstanding	2,343,167		2,343,167		2,339,667
Exercisable, average exercise price per share	$ 200.48		$ 200.48
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 200,000		$ 0
Stock options granted			740,000
Minimum [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, number of years			3 years
Maximum [Member] \| Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, number of years			5 years