Goodwill and Identifiable Assets (Tables)

3 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

The changes in the carrying amount of goodwill for three months ended March 31, 2018 and the year ended December 31, 2017 were as follows (in thousands):



	Apex Segment		Oxford 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
Translation adjustment	—		793		793
Balance as of March 31, 2018	$	662,084	$	232,804	$	894,888

Schedule of Acquired Intangible Assets

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



		March 31, 2018						December 31, 2017
	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	$	202,800	$	123,802	$	78,998	$	202,588	$	119,272	$	83,316
Contractor relationships	2 - 5 years	71,200		61,191		10,009		71,121		59,174		11,947
Non-compete agreements	2 - 7 years	11,908		7,013		4,895		11,850		6,600		5,250
In-use software	6 years	18,900		13,603		5,297		18,900		12,816		6,084
Favorable contracts	5 years	900		706		194		900		673		227
		305,708		206,315		99,393		305,359		198,535		106,824
Not subject to amortization:
Trademarks		245,977		—		245,977		245,942		—		245,942
Total		$	551,685	$	206,315	$	345,370	$	551,301	$	198,535	$	352,766

Schedule of Estimated Future Amortization Expense

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



Remainder of 2018	$	22,765
2019	23,311
2020	15,633
2021	12,785
2022	8,060
Thereafter	16,839
	$	99,393