SEGMENT AND GEOGRAPHIC DATA Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) segments	Dec. 31, 2017 USD ($) Segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments										3	3
Revenue, from external customers									$ 456,721			$ 422,744	$ 463,197
Revenue from Related Parties									0			0	0
Total revenue	$ 121,617	$ 118,108	$ 113,591	$ 103,405	$ 100,314	$ 108,136	$ 113,067	$ 101,227	456,721			422,744	463,197
Gross margin, from external customers									186,736			174,417	187,710
Inter-segment gross margin									0			0	0
Gross margin	48,733	$ 47,245	$ 48,326	$ 42,432	42,774	$ 43,542	$ 46,839	$ 41,262	186,736			174,417	187,710
Gain (loss) on sale and exit of businesses									0			0	19,835
Business reorganization									712			1,580	5,828
Goodwill, Impairment Loss									1,909			0	0
EBITDA (loss) (a)									2,515			(4,744)	6,820
Depreciation and amortization									2,748			3,090	3,845
Intercompany interest income (expense), net									0			0	0
Interest income (expense), net									(403)			(357)	(722)
Income (loss) from continuing operations before provision for income taxes									(636)			(8,191)	2,253
Provision for (benefit from) income taxes from continuing operations									2,284			742	646
Accounts receivable, net	71,878				58,517				71,878	$ 71,878	$ 71,878	58,517	62,420
Long-lived assets, net of accumulated depreciation and amortization	6,337				8,938				6,337	6,337	6,337	8,938	9,951
Total assets	111,640				101,812				111,640	111,640	111,640	101,812	124,949
Hudson Americas
Segment Reporting Information [Line Items]
Revenue, from external customers									16,196			15,561	28,627
Revenue from Related Parties									47			20	41
Total revenue									16,243			15,581	28,668
Gross margin, from external customers									14,420			13,609	16,111
Inter-segment gross margin									30			(14)	25
Gross margin									14,450			13,595	16,136
Gain (loss) on sale and exit of businesses													15,918
Business reorganization									(82)			(39)	1,108
Goodwill, Impairment Loss									0
EBITDA (loss) (a)									1,578			770	13,354
Depreciation and amortization									2			49	604
Intercompany interest income (expense), net									0			0	0
Interest income (expense), net									0			0	(342)
Income (loss) from continuing operations before provision for income taxes									1,576			721	12,408
Provision for (benefit from) income taxes from continuing operations									63			30	58
Accounts receivable, net	3,112				2,507				3,112	3,112	3,112	2,507	3,155
Long-lived assets, net of accumulated depreciation and amortization	0				2				0	0	0	2	36
Total assets	5,892				5,880				5,892	5,892	5,892	5,880	7,766
Hudson Asia Pacific
Segment Reporting Information [Line Items]
Revenue, from external customers									282,824			236,839	219,391
Revenue from Related Parties									0			0	0
Total revenue									282,824			236,839	219,391
Gross margin, from external customers									93,623			84,126	89,682
Inter-segment gross margin									(246)			(271)	(477)
Gross margin									93,377			83,855	89,205
Gain (loss) on sale and exit of businesses													0
Business reorganization									1			248	669
Goodwill, Impairment Loss									1,909
EBITDA (loss) (a)									2,504			(338)	2,851
Depreciation and amortization									1,711			1,744	1,951
Intercompany interest income (expense), net									0			0	0
Interest income (expense), net									(394)			(318)	(276)
Income (loss) from continuing operations before provision for income taxes									399			(2,400)	624
Provision for (benefit from) income taxes from continuing operations									81			(2,040)	776
Accounts receivable, net	40,083				32,271				40,083	40,083	40,083	32,271	29,824
Long-lived assets, net of accumulated depreciation and amortization	4,965				7,049				4,965	4,965	4,965	7,049	7,382
Total assets	56,519				51,331				56,519	56,519	56,519	51,331	49,246
Hudson Europe
Segment Reporting Information [Line Items]
Revenue, from external customers									157,701			170,344	215,179
Revenue from Related Parties									277			314	498
Total revenue									157,978			170,658	215,677
Gross margin, from external customers									78,693			76,682	81,917
Inter-segment gross margin									216			285	451
Gross margin									78,909			76,967	82,368
Gain (loss) on sale and exit of businesses													3,917
Business reorganization									815			1,387	2,883
Goodwill, Impairment Loss									0
EBITDA (loss) (a)									4,583			1,064	(207)
Depreciation and amortization									676			892	802
Intercompany interest income (expense), net									(182)			(204)	(526)
Interest income (expense), net									2			(32)	(94)
Income (loss) from continuing operations before provision for income taxes									3,727			(64)	(1,629)
Provision for (benefit from) income taxes from continuing operations									1,750			2,761	(176)
Accounts receivable, net	28,683				23,739				28,683	28,683	28,683	23,739	29,441
Long-lived assets, net of accumulated depreciation and amortization	1,372				1,528				1,372	1,372	1,372	1,528	1,859
Total assets	47,066				40,790				47,066	47,066	47,066	40,790	53,557
Corporate
Segment Reporting Information [Line Items]
Revenue, from external customers									0			0	0
Revenue from Related Parties									0			0	0
Total revenue									0			0	0
Gross margin, from external customers									0			0	0
Inter-segment gross margin									0			0	0
Gross margin									0			0	0
Gain (loss) on sale and exit of businesses													0
Business reorganization									(22)			(16)	1,168
Goodwill, Impairment Loss									0
EBITDA (loss) (a)									(6,150)			(6,240)	(9,178)
Depreciation and amortization									359			405	488
Intercompany interest income (expense), net									182			204	526
Interest income (expense), net									(11)			(7)	(10)
Income (loss) from continuing operations before provision for income taxes									(6,338)			(6,448)	(9,150)
Provision for (benefit from) income taxes from continuing operations									390			(9)	(12)
Accounts receivable, net	0				0				0	0	0	0	0
Long-lived assets, net of accumulated depreciation and amortization	0				359				0	0	0	359	674
Total assets	2,163				3,811				2,163	2,163	2,163	3,811	14,380
Inter- segment elimination
Segment Reporting Information [Line Items]
Revenue, from external customers									0			0	0
Revenue from Related Parties									(324)			(334)	(539)
Total revenue									(324)			(334)	(539)
Gross margin, from external customers									0			0	0
Inter-segment gross margin									0			0	1
Gross margin									0			0	1
Gain (loss) on sale and exit of businesses													0
Business reorganization									0			0	0
Goodwill, Impairment Loss									0
EBITDA (loss) (a)									0			0	0
Depreciation and amortization									0			0	0
Intercompany interest income (expense), net									0			0	0
Interest income (expense), net									0			0	0
Income (loss) from continuing operations before provision for income taxes									0			0	0
Provision for (benefit from) income taxes from continuing operations									0			0	0
Accounts receivable, net	0				0				0	0	0	0	0
Long-lived assets, net of accumulated depreciation and amortization	0				0				0	0	0	0	0
Total assets	$ 0				$ 0				$ 0	$ 0	$ 0	$ 0	$ 0