Goodwill and Identifiable Assets (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The changes in the carrying amount of goodwill for the years ended December 31, 2018 and 2017 are as follows (in thousands):

	Apex Segment		Oxford Segment			ECS Segment		Total
Balance as of December 31, 2016	$	644,617	$	228,896		$	—	$	873,513
Stratacuity acquisition	17,467		—			—		17,467
Translation adjustment	—		3,115			—		3,115
Balance as of December 31, 2017	662,084		232,011			—		894,095
ECS acquisition	—		—			528,207		528,207
Translation adjustment	—		(1,226		)	—		(1,226		)
Balance as of December 31, 2018	$	662,084	$	230,785		$	528,207	$	1,421,076

Schedule of Acquired Intangible Assets

As of December 31, 2018 and 2017, the Company had the following acquired intangible assets (in thousands):

		2018						2017
	Estimated Useful Life	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
Subject to amortization:
Customer and contractual relationships	2 - 12.75 years	$	346,799	$	145,424	$	201,375	$	202,588	$	119,272	$	83,316
Contractor relationships	2 - 5 years	71,104		67,072		4,032		71,121		59,174		11,947
Backlog	2.75 years	23,100		17,740		5,360		—		—		—
Non-compete agreements	2 - 7 years	22,128		9,907		12,221		11,850		6,600		5,250
In-use software	6 years	18,900		15,966		2,934		18,900		12,816		6,084
Favorable contracts	5 years	1,400		853		547		900		673		227
		483,431		256,962		226,469		305,359		198,535		106,824
Not subject to amortization:
Trademarks		262,222		—		262,222		245,942		—		245,942
Total		$	745,653	$	256,962	$	488,691	$	551,301	$	198,535	$	352,766

Schedule of Estimated Future Amortization Expense

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

2019	$	47,280
2020	36,401
2021	30,705
2022	22,970
2023	19,622
Thereafter	69,491
	$	226,469