Aggregate number of common shares reserved for future issuance.

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

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- Definition

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

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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 and Employee Benefit Plan - Equity Incentive Plan (Additional Information) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price, outstanding options (in dollars per share)	$ 21.27	$ 20.76	$ 25.93
2002 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options (in shares)	1,265,656	1,856,154
Weighted average exercise price, outstanding options (in dollars per share)	$ 26.64
2002 Stock Plan \| Class B common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Stock-based compensation vesting period	4 years
Number of outstanding options (in shares)	1,265,656
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price, outstanding options (in dollars per share)	$ 27.43
2012 Equity Incentive Plan \| Class B common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Stock-based compensation vesting period	4 years
Number of outstanding options (in shares)	8,877,792	9,982,756
2012 Equity Incentive Plan \| Class B common stock \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	504,034	6,656,094
2018 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price, outstanding options (in dollars per share)	$ 9.48
Shares reserved for future issuance (in shares)	20,233,754	17,233,144
2018 Equity Incentive Plan \| Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Stock-based compensation vesting period	4 years
Number of outstanding options (in shares)	5,210,823	5,998,406
2018 Equity Incentive Plan \| Class A common stock \| RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options (in shares)	5,914,754	3,456,172