STOCKHOLDERS' EQUITY - Schedule of Common Stock (Details) - shares	1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2023	Aug. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued and outstanding, beginning balance (in shares)			59,674,960	62,087,303	60,555,661	65,968,224
Shares issued and outstanding, beginning balance (in shares)			59,674,960	62,087,303	60,555,661	65,968,224
Issuance of common stock for the acquisition of Zenefits (in shares)			0	0	0	193,221
Repurchase of common stock (in shares)	(3,364,486)	(5,981,308)	(9,345,794)	0	(10,611,683)	(4,419,423)
Awards effectively repurchased for required employee withholding taxes (in shares)			(56,519)	(78,718)	(159,941)	(176,514)
Shares issued and outstanding, ending balance (in shares)	50,507,590		50,507,590	62,229,506	50,507,590	62,229,506
Shares issued and outstanding, ending balance (in shares)	50,507,590		50,507,590	62,229,506	50,507,590	62,229,506
Issuance of common stock from vested restricted stock units
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from vested restricted stock units (in shares)			161,125	199,171	464,051	496,051
Issuance of common stock from exercise of stock options
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from exercise of stock options (in shares)			73,818	21,750	155,485	94,139
Issuance of common stock for employee stock purchase plan
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee stock purchase plan (in shares)			0	0	104,017	73,808