Business Segments (Tables)

12 Months Ended

Dec. 31, 2016

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

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

	Year ended December 31, 2016
	Apex		Oxford		Corporate(1)			Total
Revenues	$	1,836,488	$	603,925	$	—		$	2,440,413
Gross profit	548,421		246,762		—			795,183
Operating income	195,133		51,294		(56,701		)	189,726
Amortization	34,359		5,269		—			39,628

	Year ended December 31, 2015
	Apex		Oxford		Corporate(1)			Total
Revenues	$	1,493,608	$	571,400	$	—		$	2,065,008
Gross profit	439,586		239,159		—			678,745
Operating income	151,450		59,059		(58,401		)	152,108
Amortization	28,371		6,096		—			34,467

	Year ended December 31, 2014
	Apex		Oxford		Corporate(1)			Total
Revenues	$	1,198,140	$	526,601	$	—		$	1,724,741
Gross profit	338,023		219,412		—			557,435
Operating income	121,838		58,741		(42,797		)	137,782
Amortization	16,356		5,765		9			22,130

Revenue by Type [Table Text Block]

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

	Year Ended December 31,
	2016		2015		2014
Revenues:
Assignment	$	2,312,271	$	1,947,001	$	1,641,706
Permanent placement	128,142		118,007		83,035
	$	2,440,413	$	2,065,008	$	1,724,741

Disclosure on Geographic Areas, Description of Revenue from External Customers

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

	Year Ended December 31,
	2016		2015		2014
Revenues:
Domestic	$	2,324,713	$	1,972,888	$	1,643,598
Foreign	115,700		92,120		81,143
	$	2,440,413	$	2,065,008	$	1,724,741

Long Lived Assets By Geographic Location Domestic And Foreign

The following table presents long-lived assets by geographic location (in thousands):

	December 31,
	2016		2015
Long-lived assets:
Domestic	$	55,801	$	52,228
Foreign	1,141		968
	$	56,942	$	53,196