Business Segments (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from External Customer [Line Items]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

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



	Year ended December 31,
	2018			2017			2016
Apex:
Revenues	$	2,300,242		$	2,037,154		$	1,836,488
Gross profit	687,861			606,294			548,421
Operating income	262,297			222,010			195,133
Amortization	26,185			29,361			34,359
Oxford:
Revenues	$	606,510		$	588,770		$	603,925
Gross profit	248,875			243,779			246,762
Operating income	54,142			53,787			51,294
Amortization	4,179			4,083			5,269
ECS:
Revenues	$	493,029		$	—		$	—
Gross profit	86,915			—			—
Operating income	15,514			—			—
Amortization	28,142			—			—
Corporate:
Operating loss⁽¹⁾	$	(71,805	)	$	(51,061	)	$	(56,701	)
Consolidated:
Revenues	$	3,399,781		$	2,625,924		$	2,440,413
Gross profit	1,023,651			850,073			795,183
Operating income	260,148			224,736			189,726
Amortization	58,506			33,444			39,628

_________

⁽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.

Disaggregation of Revenue [Table Text Block]

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



	Year Ended December 31,
	2018		2017		2016
Apex:
Assignment	$	2,244,470	$	1,993,256	$	1,791,566
Permanent placement	55,772		43,898		44,922
	$	2,300,242	$	2,037,154	$	1,836,488
Oxford:
Assignment	$	516,045	$	503,058	$	520,705
Permanent placement	90,465		85,712		83,220
	$	606,510	$	588,770	$	603,925
ECS:
Firm-fixed-price	$	133,146	$	—	$	—
Time and Materials	143,434		—		—
Cost-plus-fixed-fee	216,449		—		—
	$	493,029	$	—	$	—
Consolidated	$	3,399,781	$	2,625,924	$	2,440,413

Revenue from External Customers by Products and Services [Table Text Block]

The following table presents the ECS segment revenues by customer type (in thousands):



	Year Ended
	December 31, 2018
Department of Defense and Intelligence Agencies	$	310,984
Federal Civilian	150,922
Commercial and Other	31,123
	$	493,029

Revenue from External Customers by Geographic Areas [Table Text Block]

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,
	2018		2017		2016
Domestic	$	3,241,804	$	2,494,446	$	2,324,713
Foreign	157,977		131,478		115,700
	$	3,399,781	$	2,625,924	$	2,440,413

Reconciliation of Assets from Segment to Consolidated [Table Text Block]

The following table presents total assets by reportable segment (in thousands):



	December 31,
	2018		2017
Apex	$	1,368,548	$	1,357,246
Oxford	421,199		424,593
ECS	865,610		—
Corporate⁽¹⁾	32,494		28,290
	$	2,687,851	$	1,810,129

Long-lived Assets by Geographic Areas [Table Text Block]

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



	December 31,
	2018		2017
Domestic	$	76,742	$	56,137
Foreign	2,381		1,859
	$	79,123	$	57,996