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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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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 tax benefit from exercise of option under share-based payment arrangement.

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Amount of transfers into (out of) an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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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 maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Cash received on stock transaction after deduction of issuance costs.

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The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

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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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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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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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

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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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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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STOCKHOLDERS' EQUITY - Narrative (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) vote $ / shares shares	Dec. 31, 2019 USD ($) vote $ / shares shares	Dec. 31, 2018 USD ($)
Limited Partners' Capital Account [Line Items]
Reduction of goodwill		$ 2,619
Preferred stock authorized to issue (up to) (in shares) \| shares	944,000
Shares issued \| shares	0	0
Total fair value of other stock awards vested	$ 18,329	$ 8,177	$ 10,529
Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	76
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	0	0	474
Aggregate intrinsic value of stock options exercised	296	19,475	1,916
Restricted Stock, Restricted Stock Units and Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	7,965	7,036	7,821
Income benefit associated with stock-based compensation expense	6,796	97	23
Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 3,751
Market-based Performance Stock Units
Limited Partners' Capital Account [Line Items]
Weighted average fair value of market-based performance (in dollars per share) \| $ / shares	$ 50.25
Risk-free interest rate	0.57%
Expected volatility	31.00%
Expected dividend yield	0.00%
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense	$ 254	$ 186	$ 150
Non-Employee Director \| Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Options vesting period	3 years
Maximum \| Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense	$ 4,597
Weighted Average \| Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period	2 years 3 months 18 days
Weighted Average \| Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period	1 year 9 months 18 days
Weighted Average \| Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period	1 year 8 months 12 days
2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Options granted period	10 years
2016 Incentive Plan \| Minimum
Limited Partners' Capital Account [Line Items]
Options vesting period	1 year
2016 Incentive Plan \| Maximum
Limited Partners' Capital Account [Line Items]
Options vesting period	4 years
Class A Common Stock
Limited Partners' Capital Account [Line Items]
Vote for each share held (in votes per share) \| vote	1
Number of shares available for future grant \| shares	74,000
Class A Common Stock \| Public Stock Offering
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued \| shares	2,703,000	3,565,000
Sale of stock, price per share (in dollars per share) \| $ / shares	$ 56.00	$ 29.50
Sale of stock, net proceeds	$ 144,790	$ 100,446
Class A Common Stock \| Unregistered Sale
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued \| shares		59,000
Sale of stock, price per share (in dollars per share) \| $ / shares		$ 44.15
Sale of stock, net proceeds		$ 2,619
Class A Common Stock \| 2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares \| shares	2,250,000
Common stock, additional authorized shares \| shares	2,723,000
Number of shares available for future grant \| shares	1,104,000
Class B Common Stock
Limited Partners' Capital Account [Line Items]
Vote for each share held (in votes per share) \| vote	10	10