Goodwill and Identifiable Assets (Tables)

6 Months Ended

Jun. 30, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

The changes in the carrying amount of goodwill for the year ended December 31, 2015 and the six months ended June 30, 2016 are as follows (in thousands):



	Apex Segment			Oxford Segment			Total
Balance as of December 31, 2014	$	287,951		$	224,109		$	512,060
Creative Circle acquisition	358,029			—			358,029
LabResource acquisition	—			6,449			6,449
Translation adjustment	(1,363		)	(269		)	(1,632		)
Balance as of December 31, 2015	644,617			230,289			874,906
Translation adjustment	(80		)	93			13
Balance as of June 30, 2016	$	644,537		$	230,382		$	874,919

Schedule of Acquired Intangible Assets

Acquired intangible assets consisted of the following (in thousands):



		As of June 30, 2016						As of December 31, 2015
	Estimated Useful Life	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Subject to amortization:
Customer relationships	2 - 10 years	$	196,608	$	86,812	$	109,796	$	196,472	$	74,640	$	121,832
Contractor relationships	2 - 5 years	69,785		45,692		24,093		69,764		40,124		29,640
Non-compete agreements	2 - 7 years	10,881		4,067		6,814		10,874		3,163		7,711
In-use software	6 years	18,900		8,091		10,809		18,900		6,516		12,384
Favorable contracts	5 years	900		313		587		900		172		728
		297,074		144,975		152,099		296,910		124,615		172,295
Not subject to amortization:
Trademarks		245,688		—		245,688		245,630		—		245,630
Total		$	542,762	$	144,975	$	397,787	$	542,540	$	124,615	$	417,925

Schedule of Estimated Future Amortization Expense

Estimated amortization expense is as follows (in thousands):



Remainder of 2016	$	19,472
2017	33,029
2018	28,905
2019	21,998
2020	14,500
Thereafter	34,195
	$	152,099