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Share-based Compensation Arrangement by Share-based Payment Award, Settlement Period After Vesting

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Stock Repurchased During Period, Options, Value

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Stock Returned During Period, Shares

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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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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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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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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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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 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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Price of a single share of a number of saleable stocks of a company.

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

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Number of shares that have been repurchased and retired during the period.

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Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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STOCK-BASED COMPENSATION - Narrative (Details) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) tranche shares	Feb. 28, 2021 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) tranche shares	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) tranche shares	Jun. 30, 2020 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value, exercised					$ 17,970
Unrecognized compensation cost, options	$ 23,972		$ 23,972		23,972
Unrecognized compensation cost	$ 54,755		54,755		54,755
Fair market value of share price (in usd per share) \| $ / shares		$ 38.08
Payments for repurchase of stock options					7,335	$ 0
Compensation expense			$ 2,907	$ 1,681	5,458	$ 2,835
Options repurchased					7,335
Common stock repurchased and retired					868
Additional Paid-in Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options repurchased					7,335
Common stock repurchased and retired					$ 868
Tender Offer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, price per share (in usd per share) \| $ / shares		$ 59.77
Payments for repurchase of stock options		$ 13,479
Compensation expense		$ 5,275
Options recycled back into option pool (in shares) \| shares		220
Common stock repurchased and retired (in shares) \| shares		23
Common stock repurchased and retired		$ 868
Tender Offer \| Additional Paid-in Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options repurchased		$ 7,335
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, weighted-average period of recognition					2 years
Number of options available for grant (in shares) \| shares	114		114		114
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, grants in period (in shares) \| shares					561
Unrecognized compensation cost, weighted-average period of recognition					4 years
Unrecognized compensation expense, excluding options	$ 30,783		$ 30,783		$ 30,783
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, excluding options	$ 100,543		$ 100,543		$ 100,543
Performance Shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, weighted-average period of recognition	1 year
Performance Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, weighted-average period of recognition	7 years
Performance Shares \| Founders
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, grants in period (in shares) \| shares	1,800
Settlement period after vesting	1 year
Award vesting percentage	25.00%
Award service period	10 years
Number of tranches \| tranche	10		10		10
Compensation expense					$ 0
2011 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement, number of shares authorized (in shares) \| shares	10,113		10,113		10,113
Vesting period					4 years
Share-based compensation, term of award					10 years
Incentive stock options, minimum exercise price, percent					100.00%
2011 Equity Incentive Plan \| Principal Owner
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive stock options, minimum exercise price, percent					110.00%