Segment Reporting (Tables)

3 Months Ended

Mar. 31, 2017

Segment Reporting Information [Line Items]

Schedule of Segment Reporting Information, by Segment

The following tables present revenues, gross profit, operating income and amortization by reportable segment (in thousands):

	Three Months Ended
	March 31, 2017
	Apex		Oxford		Corporate(1)			Total
Revenues	$	482,515	$	144,013	$	—		$	626,528
Gross profit	139,919		58,225		—			198,144
Operating income	46,893		8,663		(11,948		)	43,608
Amortization	7,527		937		—			8,464

	Three Months Ended
	March 31, 2016
	Apex		Oxford		Corporate(1)			Total
Revenues	$	433,155	$	148,885	$	—		$	582,040
Gross profit	126,144		61,638		—			187,782
Operating income	39,986		12,760		(14,989		)	37,757
Amortization	8,590		1,554		—			10,144

(1) Corporate expenses primarily consist of consolidated stock-based compensation expense, compensation for corporate employees, acquisition, integration and strategic planning expenses, public company expenses and depreciation expense for corporate assets.

Revenue by Type [Table Text Block]

The following table presents revenues by type (in thousands):

	Three Months Ended
	March 31,
	2017		%		2016		%
Revenues:
Assignment	$	594,515	94.9	%	$	549,552	94.4	%
Permanent placement	32,013		5.1	%	32,488		5.6	%
	$	626,528	100.0	%	$	582,040	100.0	%

Schedule of Revenue by Geographical Areas

The Company operates internationally, with operations mainly in the United States, Europe and Canada. The following table presents revenues by geographic location (in thousands):

	Three Months Ended
	March 31,
	2017		%		2016		%
Revenues:
Domestic	$	596,301	95.2	%	$	554,438	95.3	%
Foreign	30,227		4.8	%	27,602		4.7	%
	$	626,528	100.0	%	$	582,040	100.0	%