Goodwill and Identifiable Assets (Tables)

12 Months Ended

Dec. 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The changes in the carrying amount of goodwill for the years ended December 31, 2015 and 2014 are as follows (in thousands):

	Apex			Oxford			Total
Balance as of December 31, 2013	$	289,712		$	224,714		$	514,426
Translation adjustment	(1,761		)	(605		)	(2,366		)
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

Schedule of Acquired Intangible Assets

As of December 31, 2015 and 2014, the Company had the following acquired intangible assets (in thousands):

		2015						2014
	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	$	196,472	$	74,640	$	121,832	$	101,141	$	53,434	$	47,707
Contractor relationships	2 - 5 years	69,764		40,124		29,640		39,332		32,021		7,311
Non-compete agreements	2 - 7 years	10,874		3,163		7,711		3,654		1,922		1,732
Favorable contracts	5 years	900		172		728		—		—		—
In-use software	6 years	18,900		6,516		12,384		18,900		3,366		15,534
		296,910		124,615		172,295		163,027		90,743		72,284
Not subject to amortization:
Trademarks		245,630		—		245,630		178,325		—		178,325
Total		$	542,540	$	124,615	$	417,925	$	341,352	$	90,743	$	250,609

Schedule of Estimated Future Amortization Expense

Estimated amortization for each of the next five years and thereafter are as follows (in thousands):

2016	$	39,657
2017	33,029
2018	28,904
2019	22,008
2020	14,496
Thereafter	34,201
	$	172,295