The highest aggregate value of awards an employee can be granted under the plan per period.

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The highest dollar amount from their salary that an employee is permitted to utilize with respect to the plan.

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Share-Based Compensation Arrangements By Share-Based Payment Award, Performance Shares Payout Rate

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The maximum percentage that can be achieved under the predetermined performance thresholds for the performance shares.

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The minimum percentage that can be achieved under the predetermined performance thresholds for the performance shares.

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

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Contractual term for options outstanding and currently exercisable, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Estimated period over which awards are earned, if at all, based upon the achievement of performance goals as determined by the company in exchange for the equity-based payment award, 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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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of noncash expense for share-based payment arrangement.

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the 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 offering date that participants pay for shares.

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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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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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The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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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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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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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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Percentage of vesting of award under share-based payment arrangement.

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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

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No definition available.

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- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

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Stock-Based Compensation Plans - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 09, 2020	Jun. 14, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 29,602,000	$ 36,763,000	$ 20,360,000
Stock-based compensation expense, tax benefits	5,400,000	5,900,000	$ 3,900,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value of stock options granted (in dollars per share)			$ 7.03
Total intrinsic value of stock options exercised	19,500,000	16,000,000.0	$ 15,800,000
Unrecognized compensation costs	$ 100,000
Unrecognized compensation costs, weighted average recognition periods	2 months 12 days
Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award	1 year
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award	10 years
LTIP Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation awards, award payout range, maximum	200.00%
Number of shares vested	668,240
Shares withheld to pay employees' portion of minimum payroll withholding taxes	165,237
LTIP Performance Shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	1 year
LTIP Performance Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Restricted Share Awards (RSAs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested	88,913
Shares withheld to pay employees' portion of minimum payroll withholding taxes	28,233
Requisite service period	3 years
Award vesting rights, incremental vesting percentage on anniversary of grant date	33.00%
Total Shareholder Return Awards (TSRs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Stock based compensation awards, award payout range, minimum	0.00%
Stock based compensation awards, award payout range, maximum	200.00%
Number of shares vested	199,413
Performance shares payout rate	93.00%
Shares withheld to pay employees' portion of minimum payroll withholding taxes	53,033
Unrecognized compensation costs	$ 17,600,000
Unrecognized compensation costs, weighted average recognition periods	1 year 10 months 24 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested	431,504
Shares withheld to pay employees' portion of minimum payroll withholding taxes	121,564
Requisite service period	3 years
Award vesting rights, incremental vesting percentage on anniversary of grant date	33.00%
Unrecognized compensation costs	$ 18,900,000
Unrecognized compensation costs, weighted average recognition periods	1 year 9 months 18 days
Restricted Stock Units (RSUs) \| Board Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares of common stock reserved for issuance	3,000,000
Purchase of common stock under the plan, employee annual base compensation, amount	$ 25,000
Purchase of common stock under the plan, employee annual base compensation, percentage	10.00%
Price of common stock purchased under ESPP, percentage	85.00%
Discount offered pursuant to ESPP, percentage	15.00%
Stock-based compensation expense	$ 700,000	$ 600,000	$ 500,000
2020 Equity and Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant				6,658,754
2016 Equity and Performance Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance	8,000,000
Maximum aggregate number of shares allowed per participant during any calendar year	3,000,000
Maximum aggregate value allowed per participant on the date of grant during any calendar year	$ 9,000,000
2005 Equity and Performance Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock reserved for issuance					23,250,000