Discontinued Operations - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended	9 Months Ended
	Jun. 07, 2019	Apr. 01, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) gain on sale of discontinued operations				$ 79,602	$ 0
Effective tax rates for discontinued operations				4.40%	25.60%
Cash provided by (used in) operating activities for discontinued operations				$ 5,100	$ 5,400
Cash provided by (used in) investing activities for discontinued operations				118,500	$ (900)
Discontinued Operations, Disposed of by Sale | Kforce Government Solutions, Inc.("KGS")
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total cash purchase price		$ 115,000
(Loss) gain on sale of discontinued operations		72,300
Transaction costs		$ 9,600
Income tax expense			$ 600
Discontinued Operations, Disposed of by Sale | TraumaFX
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total cash purchase price	$ 18,400
(Loss) gain on sale of discontinued operations	7,300
Transaction costs	$ 2,200
Working capital adjustment			$ 400
Contingent consideration paid				$ 600