INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2017

INTANGIBLE ASSETS

Summary of intangible assets

	Supplier relationships		Software development		Customer contracts and relationships		Others		Total
Balance as of January 1, 2015	56,654		688,061		749,027		53,356		1,547,098
Foreign exchange effect	—		123,167		327,424		14,375		464,966
Acquisition	—		118,933		—		7,495		126,428
Disposal	—		(1,182	)	—		(4,208	)	(5,390	)
Amortization	(9,083	)	(120,497	)	(164,968	)	(2,793	)	(297,341	)
Balance as of December 31, 2015	47,571		808,482		911,483		68,225		1,835,761
Foreign exchange effect	—		(60,464	)	(140,812	)	(7,509	)	(208,785	)
Acquisition	—		40,643		—		13,401		54,044
Disposal	—		(2,145	)	—		(13,050	)	(15,195	)
Amortization	(7,845	)	(149,911	)	(155,063	)	(5,316	)	(318,135	)
(-) Effect of selling of subsidiary	—		—		—		(27,749	)	(27,749	)
Balance as of December 31, 2016	39,726		636,605		615,608		28,002		1,319,941
Foreign exchange effect	—		2,947		3,835		884		7,666
Acquisition	—		37,939		—		—		37,939
Disposal	—		—		(27,652	)	—		(27,652	)
Amortization	(6,940	)	(149,150	)	(125,621	)	(3,486	)	(285,197	)
(-) Assets held for sale (note 3.4)	—		(37,512	)	(25,396	)	(17,700	)	(80,608	)
Balance as of December 31, 2017	32,786		490,829		440,774		7,700		972,089
Estimated useful lives	5 to 20 years		7 years		5 to 20 years		5 years

Summary of intangible assets by segment

	2017	2016	2015
Brazil	351,578	412,134	459,383
Special Steel	152,640	219,878	357,435
South America	1,863	7,606	13,507
North America	466,008	680,323	1,005,436
	972,089	1,319,941	1,835,761