SEGMENT AND GEOGRAPHIC DATA Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) segments	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segments	3
Total revenue	$ 16,215	$ 13,992
Gross margin	10,154	10,002
Business reorganization	0	(113)
EBITDA (loss)	(2,725)	(252)
Depreciation and amortization	0	81
Interest income (expense), net	0	0
Income (loss) from continuing operations before provision for income taxes	(2,725)	(333)
Accounts receivable, net	13,675	9,497	$ 11,545
Long-lived assets, net of accumulated depreciation and amortization (b)	7	289
Total assets	57,970	15,803	$ 111,640
Hudson Europe
Segment Reporting Information [Line Items]
Total revenue	1,508	1,899
Long-lived assets, net of accumulated depreciation and amortization (b)	0	1
Operating Segments | Hudson Americas
Segment Reporting Information [Line Items]
Total revenue	3,701	4,314
Gross margin	3,124	3,832
Business reorganization		(92)
EBITDA (loss)	291	335
Depreciation and amortization		2
Income (loss) from continuing operations before provision for income taxes	291	333
Accounts receivable, net	2,645	3,062
Long-lived assets, net of accumulated depreciation and amortization (b)	0	0
Total assets	4,292	6,145
Operating Segments | Hudson Asia Pacific
Segment Reporting Information [Line Items]
Total revenue	8,824	6,341
Gross margin	4,922	4,184
Business reorganization		0
EBITDA (loss)	544	742
Depreciation and amortization		0
Income (loss) from continuing operations before provision for income taxes	544	742
Accounts receivable, net	6,174	3,223
Long-lived assets, net of accumulated depreciation and amortization (b)	0	0
Total assets	8,242	3,548
Operating Segments | Hudson Europe
Segment Reporting Information [Line Items]
Total revenue	3,690	3,337
Gross margin	2,108	1,986
Business reorganization		1
EBITDA (loss)	11	179
Depreciation and amortization		0
Income (loss) from continuing operations before provision for income taxes	11	179
Accounts receivable, net	4,856	3,212
Long-lived assets, net of accumulated depreciation and amortization (b)	7	9
Total assets	6,750	4,320
Corporate
Segment Reporting Information [Line Items]
Total revenue	0	0
Gross margin	0	0
Business reorganization		(22)
EBITDA (loss)	(3,571)	(1,508)
Depreciation and amortization		79
Income (loss) from continuing operations before provision for income taxes	(3,571)	(1,587)
Accounts receivable, net	0	0
Long-lived assets, net of accumulated depreciation and amortization (b)	0	280
Total assets	38,686	1,790
Elimination
Segment Reporting Information [Line Items]
Total revenue	0	0
Gross margin	0	0
Business reorganization		0
EBITDA (loss)	0	0
Depreciation and amortization		0
Income (loss) from continuing operations before provision for income taxes	0	0
Accounts receivable, net	0	0
Long-lived assets, net of accumulated depreciation and amortization (b)	0	0
Total assets	$ 0	$ 0