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Percentage of compensation withheld by employees to purchase common stock.

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Percentage Of Target Award

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Share based compensation arrangement by share based payment award maximum value of shares per employee.

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Share based compensation arrangement by share based payment award options becoming exercisable.

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Share-based Compensation Arrangement by Share-based Payment Award, Look Back Commencement Period

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Share-based Compensation Arrangement by Share-based Payment Award, Purchase Period

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Stockholders' Equity And Stock-Based Compensation [Line Items]

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Terms for issuance of stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Minimum period the individual is required to perform services to be fully vested under the deferred compensation arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Discount rate from fair value on purchase date that participants pay for shares.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The highest quantity of shares an employee can purchase under the plan per period.

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

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

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The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

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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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Amount remaining of a stock repurchase plan authorized.

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Stockholders' Equity And Stock-Based Compensation (Narrative) (Details)					1 Months Ended	6 Months Ended	41 Months Ended
	Dec. 15, 2022 shares	Dec. 15, 2021 shares	Dec. 15, 2020 shares	Dec. 16, 2019 shares	Dec. 30, 2022	Mar. 31, 2023 USD ($) vote shares	Mar. 28, 2014	Sep. 30, 2022 shares
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares, Granted (in shares)						1,591,000
Vested in period (in shares)						1,103,000
Options outstanding to purchase								4,059,000
Remaining authorization to purchase additional shares \| $						$ 261,600,000
Stock options
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest \| $						$ 14,900,000
Employee stock options expected to be recognized over a weighted-average period						2 years 7 months 6 days
Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						7 years
Compensation requisite measurement period						3 years
Shares exercisable (in shares)						315,839
Restricted stock units
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						4 years
Stock options expected to vest \| $						$ 231,500,000
Employee stock options expected to be recognized over a weighted-average period						2 years 9 months 18 days
Restricted stock units \| Employees and Officers [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						4 years
Restricted stock units \| Awards Granted Prior to November 2010 [Member] \| Directors [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							1 year
Performance-Based Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Compensation requisite measurement period						3 years
Performance-Based Restricted Stock Units [Member] \| Executive Officer [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Vested of Target Award		200.00%	200.00%			200.00%
Shares exercisable (in shares)		120,602	132,276
Options outstanding to purchase		60,301	66,138			204,709
Performance-Based Restricted Stock Units [Member] \| Vesting Shares At 200% Of The Target Award Amount \| Executive Officer [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options outstanding to purchase						409,418
Performance Shares \| Executive Officer [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares, Granted (in shares)	90,613			62,000
Award vesting rights, percentage	200.00%				81.00%
Vested in period (in shares)	181,226
Awards Granted Under 2005 Stock Plan Prior To February 2011 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Terms for issuance of stock (in shares)						2
Awards Granted Under 2005 Stock Plan From February 2011 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Terms for issuance of stock (in shares)						1.6
Employee stock purchase plan
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage of compensation withheld by employees to purchase common stock						10.00%
Discount from market price on purchase date						15.00%
Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)						500,000,000		500,000,000
Common stock, shares issued (shares)						59,671,342		59,798,862
Common stock, shares outstanding (shares)						59,671,342		59,798,862
Common stock, number of votes per share \| vote						1
Class A Common Stock [Member] \| 2005 Stock Plan. [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares authorized under plan						64,000,000
Options outstanding to purchase						4,060,000
Class A Common Stock [Member] \| Employee stock purchase plan
Stockholders' Equity And Stock-Based Compensation [Line Items]
Maximum value of common stock available for eligible employees \| $						$ 25,000
Maximum number of common stock available for eligible employees (in shares)						1,000
Purchase period						6 months
Look back commencement period						1 year
Class B Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)						500,000,000		500,000,000
Common stock, shares issued (shares)						36,085,779		36,085,779
Common stock, shares outstanding (shares)						36,085,779		36,085,779
Common stock, number of votes per share \| vote						10
Options Granted From June Two Thousand Eight Member \| Stock options
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						4 years
Options Granted From June Two Thousand Eight Member \| Stock options \| One year anniversary date
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						1 year
Percentage of stock option becoming exercisable subjected to date of grant						25.00%
Options Granted From June Two Thousand Eight Member \| Stock options \| Over 36 equally installment periods following one year anniversary date
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						36 months
Awards Granted After November 2010 Member [Member] \| Restricted stock units
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						1 year
Minimum [Member] \| Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Vested of Target Award						0.00%
Minimum [Member] \| Performance-Based Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Vested of Target Award						0.00%
Minimum [Member] \| Options Granted From June Two Thousand Eight Member \| Stock options
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options expiration period						3 months
Maximum [Member] \| Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Vested of Target Award						125.00%
Maximum [Member] \| Performance-Based Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Vested of Target Award						200.00%
Maximum [Member] \| Options Granted From June Two Thousand Eight Member \| Stock options
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options expiration period						10 years