Goodwill and Identifiable Assets (Tables)

9 Months Ended

Sep. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

The changes in the carrying amount of goodwill for the nine months ended September 30, 2019 and the year ended December 31, 2018 were as follows (in millions):



	Apex Segment		Oxford Segment			ECS Segment		Total
Balance as of December 31, 2017	$	662.1	$	232.0		$	—	$	894.1
ECS acquisition	—		—			528.2		528.2
Translation adjustment	—		(1.2		)	—		(1.2		)
Balance as of December 31, 2018	662.1		230.8			528.2		1,421.1
DHA acquisition	—		—			24.7		24.7
Translation adjustment	—		(1.1		)	—		(1.1		)
Balance as of September 30, 2019	$	662.1	$	229.7		$	552.9	$	1,444.7

Schedule of Acquired Intangible Assets

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



		September 30, 2019						December 31, 2018
	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	$	362.1	$	170.7	$	191.4	$	346.9	$	145.4	$	201.5
Contractor relationships	2 - 5 years	71.0		70.5		0.5		71.1		67.1		4.0
Backlog	1 - 2.75 years	25.0		22.3		2.7		23.1		17.7		5.4
Non-compete agreements	2 - 7 years	23.6		12.8		10.8		22.1		9.9		12.2
In-use software	6 years	18.9		18.3		0.6		18.9		16.0		2.9
Favorable contracts	5 years	—		—		—		1.4		0.9		0.5
		500.6		294.6		206.0		483.5		257.0		226.5
Not subject to amortization:
Trademarks⁽¹⁾		258.9		—		258.9		262.2		—		262.2
Total		$	759.5	$	294.6	$	464.9	$	745.7	$	257.0	$	488.7

⁽¹⁾ Certain foreign trademarks totaling $3.3 million were written off during the second quarter of 2019.

Schedule of Estimated Future Amortization Expense

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



Remainder of 2019	$	11.7
2020	38.1
2021	32.5
2022	24.9
2023	21.7
Thereafter	77.1
	$	206.0