Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2016

Goodwill And Intangible Assets Disclosure [Abstract]

Summary of Goodwill

The following table summarizes goodwill activity for the three years in the period ended December 31, 2016 (in millions):

			Accumulated			Goodwill,
	Goodwill		Impairments			Net
Balance at January 1, 2014	$	18.1	$	(11.8	)	$	6.3
No activity in 2014		—		—			—
Balance at December 31, 2014		18.1		(11.8	)		6.3
No activity in 2015		—		—			—
Balance at December 31, 2015		18.1		(11.8	)		6.3
Addition in 2016		3.2		—			3.2
Balance at December 31, 2016	$	21.3	$	(11.8	)	$	9.5

Summary of Other Intangible Assets

Information regarding the Company’s other amortizable intangible assets is as follows (in millions):

					Accumulated
	Cost				Amortization
	2016		2015		2016		2015
Customer relationships	$	4.9	$	1.4	$	1.1	$	0.9
Trademarks	1.6			0.0		0.2		0.0
Other	1.6			0.0		0.4		0.0
Total amortizable intangible assets (1)	$	8.1	$	1.4	$	1.7	$	0.9

(1) Amortizable intangible assets are included in “Other Assets.”

The estimated intangible asset amortization expense, by year and in the aggregate, consisted of the following at December 31, 2016 (in millions):

	Amortization
2017	$	1.2
2018		1.2
2019		0.8
2020		0.6
2021		0.3
Thereafter		2.3
Total	$	6.4