Goodwill and Identifiable Assets (Tables)

9 Months Ended

Sep. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

The changes in the carrying amount of goodwill for nine months ended September 30, 2017 and the year ended December 31, 2016 were as follows (in thousands):



	Apex Segment		Oxford Segment			Total
Balance as of December 31, 2015	$	644,617	$	230,289		$	874,906
Translation adjustment	—		(1,393		)	(1,393		)
Balance as of December 31, 2016	644,617		228,896			873,513
Stratacuity acquisition	17,493		—			17,493
Translation adjustment	—		2,770			2,770
Balance as of September 30, 2017	$	662,110	$	231,666		$	893,776

Schedule of Acquired Intangible Assets

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



		September 30, 2017						December 31, 2016
	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	$	202,474	$	114,065	$	88,409	$	196,204	$	98,804	$	97,400
Contractor relationships	2 - 5 years	71,103		57,174		13,929		69,721		50,528		19,193
Non-compete agreements	2 - 7 years	11,845		6,145		5,700		10,861		4,922		5,939
In-use software	6 years	18,900		12,029		6,871		18,900		9,666		9,234
Favorable contracts	5 years	900		618		282		900		453		447
		305,222		190,031		115,191		296,586		164,373		132,213
Not subject to amortization:
Trademarks		245,949		—		245,949		245,517		—		245,517
Total		$	551,171	$	190,031	$	361,140	$	542,103	$	164,373	$	377,730

Schedule of Estimated Future Amortization Expense

Estimated future amortization expense is as follows (in thousands):



Remainder of 2017	$	8,483
2018	30,470
2019	23,400
2020	15,687
2021	12,806
Thereafter	24,345
	$	115,191