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Number of Tranches.

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Value 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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Aggregate grant date fair value of equity instruments other than options.

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

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Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

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

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Number, after forfeiture, of shares or units issued under share-based payment arrangement. Excludes shares or units issued under employee stock ownership plan (ESOP).

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STOCKHOLDERS' EQUITY - Awards granted (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($) tranche shares	Mar. 31, 2021 USD ($)	Mar. 07, 2022 $ / shares	Feb. 16, 2022 $ / shares
STOCKHOLDERS' EQUITY
Stock-based compensation expense \| $	$ 6.5	$ 5.4
Board of Director
STOCKHOLDERS' EQUITY
Stock-based compensation expense \| $	$ 0.8	0.9
2022 Performance share award
STOCKHOLDERS' EQUITY
Granted (in shares) \| shares	229,316
Stock value \| $	$ 4.5
2021 Performance share award
STOCKHOLDERS' EQUITY
Granted (in shares) \| shares	878,540
Stock value \| $	$ 17.3
Percentage of performance target	100.00%
2020 Performance share award
STOCKHOLDERS' EQUITY
Granted (in shares) \| shares	429,683
Stock value \| $	$ 8.5
Percentage of performance target	100.00%
Special Performance Stock
STOCKHOLDERS' EQUITY
Stock-based compensation expense \| $		1.5
Special Performance Stock \| 2021 Special PSU \| Minimum
STOCKHOLDERS' EQUITY
PSUs vesting as a percentage of performance target	80.00%
Special Performance Stock \| 2021 Special PSU \| Maximum
STOCKHOLDERS' EQUITY
PSUs vesting as a percentage of performance target	120.00%
RSU and PSU Units
STOCKHOLDERS' EQUITY
Price per share (in dollars per share) \| $ / shares				$ 19.67
Restricted stock unit
STOCKHOLDERS' EQUITY
Stock-based compensation expense \| $	$ 2.8	2.2
Restricted stock unit \| Members of management and executive officers
STOCKHOLDERS' EQUITY
Number of shares to be received for each unit \| shares	1
Performance Vesting \| Members of management and executive officers
STOCKHOLDERS' EQUITY
Granted (in shares) \| shares	688,269
Number of tranches \| tranche	3
Awards to be granted if target not achieved (in shares) \| shares	0
Performance Vesting \| Members of management and executive officers \| Minimum
STOCKHOLDERS' EQUITY
PSUs vesting as a percentage of performance target	80.00%
Percentage of performance target	50.00%
Performance Vesting \| Members of management and executive officers \| Maximum
STOCKHOLDERS' EQUITY
PSUs vesting as a percentage of performance target	120.00%
Percentage of performance target	200.00%
Performance stock unit expense
STOCKHOLDERS' EQUITY
Stock-based compensation expense \| $	$ 2.9	$ 0.8
2013 Equity Incentive Plan \| Members of management
STOCKHOLDERS' EQUITY
Granted (in shares) \| shares	688,269
Grant date fair value (in dollars) \| $	$ 13.4
Vesting period (in years)	3 years
Vesting rights percentage	33.33%
2013 Equity Incentive Plan \| RSU and PSU Units
STOCKHOLDERS' EQUITY
Price per share (in dollars per share) \| $ / shares			$ 15.21
2013 Equity Incentive Plan \| Restricted stock unit \| Members of management and executive officers
STOCKHOLDERS' EQUITY
Number of shares to be received for each unit \| shares	1
2013 Equity Incentive Plan \| Restricted stock unit \| Members of management
STOCKHOLDERS' EQUITY
Number of days from the termination of service for settlement of fully vested units	30 days
2013 Equity Incentive Plan \| Performance Vesting \| Members of management and executive officers
STOCKHOLDERS' EQUITY
Percentage of performance target	100.00%
Awards to be granted upon achieving 100% of performance target (in shares) \| shares	688,269
Class A common stock \| 2013 Equity Incentive Plan \| Stock options \| Board of Director
STOCKHOLDERS' EQUITY
Shares granted \| shares	41,650
Grant date fair value \| $	$ 0.8