Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from services	$ 215,606	$ 193,968	$ 216,779	$ 210,064	$ 215,096	$ 209,200	$ 202,757	$ 195,171	$ 836,417	$ 822,224	$ 816,484
Temporary Staffing Services
Disaggregation of Revenue [Line Items]
Revenue from services									805,260	790,654	782,448
Other Services
Disaggregation of Revenue [Line Items]
Revenue from services									31,157	31,570	34,036
Nurse and Allied Staffing
Disaggregation of Revenue [Line Items]
Revenue from services									757,949	732,815	718,613
Nurse and Allied Staffing | Temporary Staffing Services
Disaggregation of Revenue [Line Items]
Revenue from services									740,441	720,393	705,469
Nurse and Allied Staffing | Other Services
Disaggregation of Revenue [Line Items]
Revenue from services									17,508	12,422	13,144
Physician Staffing
Disaggregation of Revenue [Line Items]
Revenue from services									67,934	74,605	82,305
Physician Staffing | Temporary Staffing Services
Disaggregation of Revenue [Line Items]
Revenue from services									64,819	70,261	76,979
Physician Staffing | Other Services
Disaggregation of Revenue [Line Items]
Revenue from services									3,115	4,344	5,326
Search
Disaggregation of Revenue [Line Items]
Revenue from services									10,534	14,804	15,566
Search | Temporary Staffing Services
Disaggregation of Revenue [Line Items]
Revenue from services									0	0	0
Search | Other Services
Disaggregation of Revenue [Line Items]
Revenue from services									$ 10,534	$ 14,804	$ 15,566