STOCKHOLDERS' EQUITY - Schedule of Common Stock (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued and outstanding, beginning balance (in shares)	59,522,954	62,258,896	60,555,661	65,968,224
Shares issued and outstanding, beginning balance (in shares)	59,522,954	62,258,896	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)	(108,018)	(408,478)	(1,265,889)	(4,419,423)
Awards effectively repurchased for required employee withholding taxes (in shares)	(53,721)	(50,981)	(103,422)	(97,796)
Shares issued and outstanding, ending balance (in shares)	59,674,960	62,087,303	59,674,960	62,087,303
Shares issued and outstanding, ending balance (in shares)	59,674,960	62,087,303	59,674,960	62,087,303
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)	167,852	170,358	302,926	296,880
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)	41,876	43,700	81,667	72,389
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)	104,017	73,808	104,017	73,808