GOODWILL, TRADE NAMES, AND OTHER INTANGIBLE ASSETS - Goodwill Rollforward (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Goodwill [Roll Forward]
Aggregate goodwill acquired, beginning balance	$ 411,285
Accumulated impairment loss, beginning balance	(300,330)
Goodwill, net of impairment loss, beginning balance	101,066
Impairment charges	(10,142)
Reclassification of API goodwill	0
Aggregate goodwill acquired, ending balance	411,285
Accumulated impairment loss, ending balance	(310,472)
Reclassification of API goodwill	0
Goodwill, net of impairment loss, ending balance	90,924
Sale of business
Goodwill [Roll Forward]
Aggregate goodwill acquired, ending balance	9,889
Nurse And Allied Staffing
Goodwill [Roll Forward]
Aggregate goodwill acquired, beginning balance	346,130
Accumulated impairment loss, beginning balance	(259,732)
Goodwill, net of impairment loss, beginning balance	86,398
Impairment charges	0
Reclassification of API goodwill	24
Aggregate goodwill acquired, ending balance	346,130
Accumulated impairment loss, ending balance	(259,732)
Reclassification of API goodwill	24
Goodwill, net of impairment loss, ending balance	86,422
Nurse And Allied Staffing | Sale of business
Goodwill [Roll Forward]
Aggregate goodwill acquired, ending balance	0
Physician Staffing
Goodwill [Roll Forward]
Aggregate goodwill acquired, beginning balance	43,405
Accumulated impairment loss, beginning balance	(40,598)
Goodwill, net of impairment loss, beginning balance	2,807
Impairment charges	0
Reclassification of API goodwill	0
Aggregate goodwill acquired, ending balance	43,405
Accumulated impairment loss, ending balance	(40,598)
Reclassification of API goodwill	0
Goodwill, net of impairment loss, ending balance	2,807
Physician Staffing | Sale of business
Goodwill [Roll Forward]
Aggregate goodwill acquired, ending balance	0
Search Services
Goodwill [Roll Forward]
Aggregate goodwill acquired, beginning balance	21,750
Accumulated impairment loss, beginning balance	0
Goodwill, net of impairment loss, beginning balance	11,861
Impairment charges	(10,142)
Reclassification of API goodwill	(24)
Aggregate goodwill acquired, ending balance	21,750
Accumulated impairment loss, ending balance	(10,142)
Reclassification of API goodwill	(24)
Goodwill, net of impairment loss, ending balance	1,695
Search Services | Sale of business
Goodwill [Roll Forward]
Aggregate goodwill acquired, ending balance	$ 9,889