Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Change in Net Carrying Amount of Goodwill by Segment

The change in the net carrying amount of goodwill for the years ended December 31, 2017 and 2016 by segment is as follows (in thousands):

	Steel Mills			Steel Products			Raw Materials			Total
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
Acquisitions			125,328			7,004			—			132,332
Translation			—			10,998			—			10,998
Balance, December 31, 2017		$	745,484		$	720,997		$	729,577		$	2,196,058

Schedule of Intangible Assets

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, 2017				December 31, 2016
	Gross Amount		Accumulated Amortization		Gross Amount		Accumulated Amortization
Customer relationships	$	1,420,224	$	641,089	$	1,295,803	$	566,884
Trademarks and trade names		176,471		77,208		161,851		66,494
Other		62,805		26,557		62,807		20,248
	$	1,659,500	$	744,854	$	1,520,461	$	653,626