Business Segments

On Assignment provides services through two operating segments, the Apex Segment and the Oxford Segment, with each addressing different sectors of the professional staffing and IT services market with distinct go-to-market strategies attuned to those sectors. The Apex Segment provides a broad spectrum of technical, digital, creative and scientific professionals for contract, contract-to-hire and permanent placement positions to Fortune 1000 and mid-market clients across the United States and Canada. The businesses in this segment include Apex Systems, Apex Life Sciences and Creative Circle. The Oxford Segment provides specialized staffing and permanent placement services in select skill and geographic markets. The businesses in this segment include Oxford, CyberCoders and Life Sciences Europe.

The Company’s management evaluates the performance of each segment primarily based on revenues, gross profit and operating income. The information in the following tables is derived directly from the segments’ internal financial reporting used for corporate management purposes. The Company's management does not evaluate, manage or measure performance of segments using asset information and such information is not readily available. Accordingly, assets by reportable segment are not disclosed.

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



	Year ended December 31, 2017
	Apex		Oxford		Corporate⁽¹⁾			Total
Revenues	$	2,037,154	$	588,770	$	—		$	2,625,924
Gross profit	606,294		243,779		—			850,073
Operating income	222,010		53,787		(51,061		)	224,736
Amortization	29,361		4,083		—			33,444



	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


(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.

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



	Year Ended December 31,
	2017		2016		2015
Revenues:
Assignment	$	2,496,314	$	2,312,271	$	1,947,001
Permanent placement	129,610		128,142		118,007
	$	2,625,924	$	2,440,413	$	2,065,008

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,
	2017		2016		2015
Revenues:
Domestic	$	2,494,446	$	2,324,713	$	1,972,888
Foreign	131,478		115,700		92,120
	$	2,625,924	$	2,440,413	$	2,065,008

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



	December 31,
	2017		2016
Long-lived assets:
Domestic	$	56,137	$	55,801
Foreign	1,859		1,141
	$	57,996	$	56,942