SEGMENT AND GEOGRAPHIC DATA - Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) Segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | Segment	3
Revenue, from external customers	$ 51,917	$ 34,461
Inter-segment revenue	0	0
Revenue	51,917	34,461
Adjusted net revenue, from external customers	25,573	12,718
Inter-segment adjusted net revenue	0	0
Total adjusted net revenue	25,573	12,718
EBITDA (loss)	3,877	75
Depreciation and amortization	(324)	(110)
Intercompany (expense) interest income, net	0	0
Interest income, net	2	10
Provision for (benefit from) income taxes	(536)	(178)
Net income (loss)	3,019	(203)
Accounts receivable, net	28,924	25,748	$ 25,748
Long-lived assets, net of accumulated depreciation and amortization	9,852	10,078
Total assets	63,310	61,242	$ 61,242
Inter-Segment Elimination
Segment Reporting Information [Line Items]
Revenue, from external customers	0	0
Inter-segment revenue	(96)	0
Revenue	(96)	0
Adjusted net revenue, from external customers	0	0
Inter-segment adjusted net revenue	0	0
Total adjusted net revenue	0	0
EBITDA (loss)	0	0
Depreciation and amortization	0	0
Intercompany (expense) interest income, net	0	0
Interest income, net	0	0
Provision for (benefit from) income taxes	0	0
Net income (loss)	0	0
Accounts receivable, net	0	0
Long-lived assets, net of accumulated depreciation and amortization	0	0
Total assets	0	0
Hudson Americas | Operating Segments
Segment Reporting Information [Line Items]
Revenue, from external customers	14,611	4,561
Inter-segment revenue	53	0
Revenue	14,664	4,561
Adjusted net revenue, from external customers	13,702	4,209
Inter-segment adjusted net revenue	16	0
Total adjusted net revenue	13,718	4,209
EBITDA (loss)	2,414	(278)
Depreciation and amortization	(305)	(86)
Intercompany (expense) interest income, net	0	0
Interest income, net	0	0
Provision for (benefit from) income taxes	(42)	(9)
Net income (loss)	2,067	(373)
Accounts receivable, net	11,711	8,765
Long-lived assets, net of accumulated depreciation and amortization	9,735	9,964
Total assets	26,047	22,214
Hudson Asia Pacific | Operating Segments
Segment Reporting Information [Line Items]
Revenue, from external customers	31,133	25,340
Inter-segment revenue	12	0
Revenue	31,145	25,340
Adjusted net revenue, from external customers	8,213	5,758
Inter-segment adjusted net revenue	(8)	0
Total adjusted net revenue	8,205	5,758
EBITDA (loss)	2,027	762
Depreciation and amortization	(11)	(14)
Intercompany (expense) interest income, net	(75)	(85)
Interest income, net	1	1
Provision for (benefit from) income taxes	(531)	(194)
Net income (loss)	1,411	470
Accounts receivable, net	11,761	12,073
Long-lived assets, net of accumulated depreciation and amortization	57	68
Total assets	24,119	21,744
Hudson Europe | Operating Segments
Segment Reporting Information [Line Items]
Revenue, from external customers	6,173	4,560
Inter-segment revenue	31	0
Revenue	6,204	4,560
Adjusted net revenue, from external customers	3,658	2,751
Inter-segment adjusted net revenue	(8)	0
Total adjusted net revenue	3,650	2,751
EBITDA (loss)	147	70
Depreciation and amortization	(7)	(9)
Intercompany (expense) interest income, net	0	0
Interest income, net	0	0
Provision for (benefit from) income taxes	16	(17)
Net income (loss)	156	44
Accounts receivable, net	5,452	4,910
Long-lived assets, net of accumulated depreciation and amortization	56	42
Total assets	8,472	9,370
Corporate Segment | Operating Segments
Segment Reporting Information [Line Items]
Revenue, from external customers	0	0
Inter-segment revenue	0	0
Revenue	0	0
Adjusted net revenue, from external customers	0	0
Inter-segment adjusted net revenue	0	0
Total adjusted net revenue	0	0
EBITDA (loss)	(711)	(479)
Depreciation and amortization	(1)	(1)
Intercompany (expense) interest income, net	75	85
Interest income, net	1	9
Provision for (benefit from) income taxes	21	42
Net income (loss)	(615)	(344)
Accounts receivable, net	0	0
Long-lived assets, net of accumulated depreciation and amortization	4	4
Total assets	$ 4,672	$ 7,914