Discontinued Operations - Summary of Pretax Profit (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of discontinued operations			$ 0	$ 80,004
Income from discontinued operations, net of tax	$ 0	$ 58,783	$ 0	77,664
Discontinued Operations, Disposed of by Sale | GS segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue		1,311		27,737
Direct costs		479		19,494
Gross profit		832		8,243
Selling, general and administrative expenses		1,424		6,842
Depreciation and amortization		58		307
(Loss) income from discontinued operations		(650)		1,094
Gain on sale of discontinued operations		80,004		80,004
Other income (expense), net		428		(436)
Income from discontinued operations, before income taxes		79,782		80,662
Income tax expense		20,999		2,998
Income from discontinued operations, net of tax		58,783		$ 77,664
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]
Income tax expense		$ 18,500