Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

8. Goodwill and Other Intangible Assets

The change in the net carrying amount of goodwill for the years ended December 31, 2016 and 2015 by segment is as follows (in thousands):

	Steel Mills			Steel Products			Raw Materials		Total
Balance, December 31, 2014	$	594,402		$	744,685		$	729,577	$	2,068,664
Translation		—			(53,618	)		—		(53,618	)
Other		(3,768	)		—			—		(3,768	)
Balance, December 31, 2015		590,634			691,067			729,577		2,011,278
Acquisitions		29,522			—			—		29,522
Translation		—			11,928			—		11,928
Balance, December 31, 2016	$	620,156		$	702,995		$	729,577	$	2,052,728

The majority of goodwill is not tax deductible.

Intangible assets with estimated useful lives of 5 to 22 years are amortized on a straight-line or accelerated basis and are comprised of the following (in thousands):

	December 31, 2016				December 31, 2015
	Gross Amount		Accumulated Amortization		Gross Amount		Accumulated Amortization
Customer relationships	$	1,295,803	$	566,884	$	1,185,299	$	517,817
Trademarks and trade names		161,851		66,494		155,864		57,756
Other		62,807		20,248		23,025		17,943
	$	1,520,461	$	653,626	$	1,364,188	$	593,516

During the third quarter of 2016, Nucor acquired the remaining ownership interest in a former joint venture entity that Nucor previously accounted for as an equity method investment. As a result of the transaction, Nucor obtained control and began to consolidate that entity. That entity’s intangible assets, the majority of which are patents, are included in other intangible assets, net in the consolidated balance sheet at December 31, 2016. The gross amount and related accumulated amortization of these assets were $36.3 million and $2.1 million, respectively, at December 31, 2016.

Intangible asset amortization expense was $73.9 million in 2016 ($74.3 million in 2015 and $72.4 million in 2014). Annual amortization expense is estimated to be $82.2 million in 2017, $79.0 million in 2018, $76.1 million in 2019, $73.7 million in 2020 and $72.5 million in 2021.

The Company completed its annual goodwill impairment testing as of the first day of the fourth quarters of 2016, 2015 and 2014 and concluded that as of such dates there was no impairment of goodwill for any of its reporting units. We do not believe there are any reporting units at significant risk of goodwill impairment in the next twelve months. However, assumptions in estimating reporting unit fair values are subject to a high degree of judgment and complexity. Changes in assumptions and estimates may affect the estimated reporting unit fair values and could result in impairment charges in future periods.

There are no significant historical accumulated impairment charges, by segment or in the aggregate, related to goodwill.