STOCK-BASED COMPENSATION - Narrative (Details)			1 Months Ended			3 Months Ended		9 Months Ended
	Jan. 01, 2024 shares	Jan. 01, 2022	Mar. 31, 2024 shares	Nov. 30, 2021 $ / shares shares	May 31, 2021 USD ($) purchase_period shares	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2024 USD ($) shares	Sep. 30, 2023 USD ($) shares	Dec. 31, 2023 USD ($) shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options issued (in shares)						3,377,239		3,377,239		4,340,052
Shares granted (in shares)						0	0	0	0
Total unrecognized stock-based compensation expense (less than) | $						$ 0		$ 0
Stock-based compensation expense | $						48,175,000	$ 44,809,000	137,532,000	$ 132,234,000
Accrued salary, payroll tax, and employee benefit liabilities | $						43,383,000		43,383,000		$ 36,171,000
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized stock-based compensation expense | $						$ 4,600,000		$ 4,600,000
Total unrecognized compensation cost, weighted-average period								4 months 24 days
Stock-based compensation expense | $								$ 6,600,000	$ 7,900,000
Offering period (in months)					12 months
Number of purchase periods | purchase_period					2
Duration of purchase periods (in months)					6 months
Percentage of eligible compensation					15.00%
Maximum amount each participant can contribute to a defined contribution plan per calendar year | $					$ 25,000
Maximum number of shares each participant can purchase during purchase period (in shares)					2,500
Purchase price, threshold, percentage of fair market value					85.00%
Withdrawal period, before end of purchase period (in days)					15 days
Expected dividend yield utilized						0		0
Accrued salary, payroll tax, and employee benefit liabilities | $						$ 9,800,000		$ 9,800,000		$ 5,000,000.0
Common stock purchased (in shares)								276,349	316,042
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized stock-based compensation expense | $						453,800,000		$ 453,800,000
Total unrecognized compensation cost, weighted-average period								2 years 7 months 6 days
Shares granted (in shares)								3,612,068
Restricted Stock Units | IPO | Quarterly or Annual Vesting Schedule
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting period (in years)								4 years
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting period (in years)			3 years
Total unrecognized stock-based compensation expense | $						$ 4,600,000		$ 4,600,000
Total unrecognized compensation cost, weighted-average period								1 year 8 months 12 days
Shares granted (in shares)			46,986					112,255
Award payout range, percentage								1
Performance Shares | Revenue Performance Goals
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted (in shares)								35,239
Percentage of awards								75.00%
Performance Shares | Revenue Performance Goals | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award payout range, percentage								0
Performance Shares | Revenue Performance Goals | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award payout range, percentage								2
Performance Shares | Non-GAAP Operating Margin Performance
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted (in shares)								11,747
Percentage of awards								25.00%
Performance Shares | Non-GAAP Operating Margin Performance | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award payout range, percentage								0
Performance Shares | Non-GAAP Operating Margin Performance | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award payout range, percentage								1.50
Performance Shares | Final Vesting, After February 20, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting period (in years)								2 years
Performance Shares | On Or After February 20, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award payout range, percentage								0.33
Restricted Stock Awards | Levelset
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vesting period (in years)				2 years
Issuance of unregistered common stock for certain employees (in shares)				199,670
Business acquisition, vesting period				2 years
Share price (in dollars per share) | $ / shares				$ 95.05
Stock-based compensation expense | $								$ 0	$ 7,700,000
Stock-based compensation expense related to early vested RSAs | $									5,500,000
Holdback amount expensed | $									$ 3,400,000
Common Stock | Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares outstanding as a percent					1.00%
Maximum number of additional shares of common stock that may be issued (in shares)					3,900,000
Maximum amount common stock that may be issued (in shares)	1,448,064				5,332,064
Period of common stock reserved for issuance (in years)					10 years
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options issued (in shares)						0		0
2021 Equity Incentive Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for issuance (in shares)						33,973,395		33,973,395		44,622,937
Shares outstanding as a percent		5.00%
Maximum number of additional shares of common stock that may be issued (in shares)	7,240,323
Maximum amount common stock that may be issued (in shares)						51,863,260		51,863,260