Goodwill and Identifiable Assets (Tables)

3 Months Ended

Mar. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

The changes in the carrying amount of goodwill for three months ended March 31, 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
Translation adjustment	—		359			359
Balance as of March 31, 2017	$	644,617	$	229,255		$	873,872

Schedule of Acquired Intangible Assets

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



		As of March 31, 2017						As of 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	$	196,318	$	103,708	$	92,610	$	196,204	$	98,804	$	97,400
Contractor relationships	2 - 5 years	69,739		52,971		16,768		69,721		50,528		19,193
Non-compete agreements	2 - 7 years	10,866		5,308		5,558		10,861		4,922		5,939
In-use software	6 years	18,900		10,454		8,446		18,900		9,666		9,234
Favorable contracts	5 years	900		508		392		900		453		447
		296,723		172,949		123,774		296,586		164,373		132,213
Not subject to amortization:
Trademarks		245,565		—		245,565		245,517		—		245,517
Total		$	542,288	$	172,949	$	369,339	$	542,103	$	164,373	$	377,730

Schedule of Estimated Future Amortization Expense

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



Remainder of 2017	$	24,392
2018	28,844
2019	21,965
2020	14,463
2021	11,760
Thereafter	22,350
	$	123,774