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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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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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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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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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Net number of non-option equity instruments granted to participants.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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Stock Options and Stock Appreciation Rights - Options (Details) - USD ($)		3 Months Ended
	Apr. 18, 2022	Mar. 31, 2023	Mar. 31, 2022	Apr. 05, 2012
Employee Stock Options
Stock Options, Aggregate intrinsic value
Stock-based compensation expense		$ 102,000	$ 121,000
Employee Stock Options \| 2012 Plan
Stock option details
Shares available for future grants				800,000
Maximum exercisable period for granted share-based compensation		10 years
Stock option activity
Options outstanding at the beginning of the period (in shares)		461,822
Less:
Exercise of stock options (in shares)		3,537
Options forfeited (in shares)		2,938
Options outstanding at the end of the period (in shares)		455,347
Options fully vested and exercisable at the end of the period (in shares)		257,932
Stock Options, Weighted average exercise price
Options outstanding at the beginning, weighted average exercise price (in dollars per share)		$ 29.67
Less:
Options exercised, weighted average exercise price (in dollars per share)		24.00
Options forfeited, weighted average exercise price (in dollars per share)		36.51
Options outstanding at the end, weighted average exercise price (in dollars per share)		29.67
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share)		$ 25.20
Stock Options, Weighted average remaining contractual term (years)
Options outstanding at the end, weighted average remaining contractual term (years)		3 years 9 months 25 days
Options fully vested and exercisable at the end, weighted average remaining contractual term (years)		2 years 21 days
Stock Options, Aggregate intrinsic value
Options outstanding at the end, aggregate intrinsic value		$ 5,987,000
Options fully vested and exercisable at the end, aggregate intrinsic value		4,545,000
Stock-based compensation cost, unrecognized, related to non-vested options		$ 660,000
Stock-based compensation cost, unrecognized, related to non-vested options, weighted-average period of recognition		1 year 7 months 6 days
Stock Appreciation Rights
Stock Options, Aggregate intrinsic value
Stock-based compensation expense			$ 166,000
Stock Appreciation Rights \| SAR Plan
Stock option details
Shares available for future grants	750,000
Maximum exercisable period for granted share-based compensation	10 years
Number of rights issued		502,250
Vesting period	8 years
Incentive Stock Options to 10 Percent Shareholders \| 2012 Plan
Stock option details
Maximum exercisable period for granted share-based compensation		5 years