ACQUISITIONS - Additional Information (Details) - USD ($) shares in Thousands, $ in Thousands			3 Months Ended		12 Months Ended
	Apr. 01, 2021	Feb. 01, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Business Acquisition [Line Items]
Payments to acquire business			$ 0	$ 4,454
Issuance of equity for Aimtell/PushPros/Aramis, and SmarterChaos			0	15,000
Change in fair value of contingent consideration liabilities			2,591	$ 0
Contingent consideration payable - non-current			1,030		$ 1,069
Technology
Business Acquisition [Line Items]
Expected useful life					4 years
Non-competition agreements
Business Acquisition [Line Items]
Expected useful life					3 years
Maximum | Brand
Business Acquisition [Line Items]
Expected useful life					7 years
Maximum | Customer relationships
Business Acquisition [Line Items]
Expected useful life					6 years
Crisp Results
Business Acquisition [Line Items]
Consideration transferred	$ 40,000
Payments to acquire business	$ 20,000
Equity issued to acquiree (in shares)	1,600
Issuance of equity for Aimtell/PushPros/Aramis, and SmarterChaos	$ 20,000
Contingent consideration	10,000
Deferred payment	$ 5,000
Deferred payment period	18 months
Contingent Consideration			10,000
Deferred acquisition consideration payable	$ 4,600		$ 4,900
Expected useful life			5 years 7 months 6 days
Crisp Results | Scenario, Adjustment | Fair Value Mark-to-Market changes
Business Acquisition [Line Items]
Contingent Consideration			$ 4,814
Change in fair value of contingent consideration liabilities			$ 2,600
Crisp Results | Brand
Business Acquisition [Line Items]
Expected useful life			7 years
Crisp Results | Customer relationships
Business Acquisition [Line Items]
Expected useful life			6 years
Crisp Results | Maximum | Brand
Business Acquisition [Line Items]
Expected useful life			7 years
Crisp Results | Maximum | Customer relationships
Business Acquisition [Line Items]
Expected useful life			6 years
Aimtell, PushPros and Aramis
Business Acquisition [Line Items]
Consideration transferred		$ 20,000
Payments to acquire business		$ 5,000
Equity issued to acquiree (in shares)		1,290
Issuance of equity for Aimtell/PushPros/Aramis, and SmarterChaos		$ 15,000
Contingent Consideration			$ 1,030
Earnout period		3 years
Change in fair value of contingent consideration liabilities			$ (1,100)
Expected useful life			4 years
Contingent consideration payable - non-current		$ 15,000
Aimtell, PushPros and Aramis | Scenario, Adjustment | Fair Value Mark-to-Market changes
Business Acquisition [Line Items]
Contingent Consideration			$ (1,117)
Aimtell, PushPros and Aramis | Technology
Business Acquisition [Line Items]
Expected useful life			4 years
Aimtell, PushPros and Aramis | Brand
Business Acquisition [Line Items]
Expected useful life			2 years 1 month 6 days
Aimtell, PushPros and Aramis | Customer relationships
Business Acquisition [Line Items]
Expected useful life			4 years 1 month 6 days
Aimtell, PushPros and Aramis | Non-competition agreements
Business Acquisition [Line Items]
Expected useful life			3 years