Earnings Per Common Share And Share Awards [Line Items]

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- Definition

Number of stock options or SARs granted where exercise price was less than market price on date of grant.

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- Definition

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

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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- Definition

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

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- Definition

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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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

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

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- Definition

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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Earnings Per Common Share And Share Awards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Earnings Per Common Share And Share Awards [Line Items]
Anti-dilutive shares excluded from computation of diluted earnings per share	20			14			20	14
Number of SARs granted where exercise price was less than market price on date of grant							0	0
Share-based Compensation Arrangement by Share-based Payment Award, Grants in Period, Net of Forfeitures		4	7		4
Share-based Compensation Arrangement by Share-based Payment Award, Grants in Period, Weighted Average Grant Date Fair Value							$ 34.45	$ 51.88
SARs
Earnings Per Common Share And Share Awards [Line Items]
SARs expiration period							7 years
Share-based Payment Arrangement, Expense							$ 192	$ 205
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 246						$ 246
Share-based Compensation Arrangement by Share-based Payment Award, Grants in Period, Net of Forfeitures						0	11		4
Minimum \| SARs
Earnings Per Common Share And Share Awards [Line Items]
SARs vesting period							1 year
Maximum \| SARs
Earnings Per Common Share And Share Awards [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Purchased for Award							250
SARs vesting period							5 years