STOCK-BASED COMPENSATION - Summary of stock options and stock options with market conditions (Details)	3 Months Ended
	Mar. 31, 2021 USD ($) $ / shares shares
Stock options, Grant Date Fair Value Valuation
Share price (in dollars per share) | $ / shares	$ 213.00
Grant date fair value (in dollars per share) | $ / shares	$ 136.23
Option
Stock options, Shares
Outstanding at the beginning of the period (in shares) | shares	924,710
Granted (in shares) | shares	53,173
Exercised (in shares) | shares	(635)
Forfeited (in shares) | shares	(2,280)
Expired (in shares) | shares	(35)
Outstanding at the end of the period (in shares) | shares	974,933
Options exercisable at the end of the period (in shares) | shares	694,184
Stock options, Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 111.82
Granted (in dollars per share) | $ / shares	253.75
Exercised (in dollars per share) | $ / shares	271.96
Forfeited (in dollars per share) | $ / shares	267.17
Expired (in dollars per share) | $ / shares	371.25
Outstanding at the end of the period (in dollars per share) | $ / shares	119.09
Options exercisable at the end of the period (in dollars per share) | $ / shares	$ 55.13
Stock options, Weighted Average Remaining Contractual Term
Outstanding at the end of the period	4 years 6 months 7 days
Options exercisable at the end of the period	2 years 7 months 24 days
Stock options, Aggregate Intrinsic Value
Outstanding at the end of the period | $	$ 114,706,000
Options exercisable at the end of the period | $	$ 114,701,000
Stock options, Grant Date Fair Value Valuation
Vesting period	3 years
Expected term	6 years
Expected dividend rate	0.00%
Expected volatility rate	58.00%
Expected dividends | $	$ 0
Option | Minimum
Stock options, Grant Date Fair Value Valuation
Risk-free interest rate	0.59%
Option | Maximum
Stock options, Grant Date Fair Value Valuation
Risk-free interest rate	0.94%
Market options
Stock options, Shares
Outstanding at the beginning of the period (in shares) | shares	700,209
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Forfeited (in shares) | shares	0
Expired (in shares) | shares	0
Outstanding at the end of the period (in shares) | shares	700,209
Options exercisable at the end of the period (in shares) | shares	0
Stock options, Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 236.01
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	0
Expired (in dollars per share) | $ / shares	0
Outstanding at the end of the period (in dollars per share) | $ / shares	236.01
Options exercisable at the end of the period (in dollars per share) | $ / shares	$ 0
Stock options, Weighted Average Remaining Contractual Term
Outstanding at the end of the period	7 years 6 months
Options exercisable at the end of the period	0 years
Stock options, Aggregate Intrinsic Value
Outstanding at the end of the period | $	$ 11,759,000
Options exercisable at the end of the period | $	$ 0
Stock options, Grant Date Fair Value Valuation
Maximum number of shared to be earned | shares	1,169,349
Percentage of target number of shares	167.00%
Performance awards earned (in shares) | shares	481,669