Goodwill and Other Intangible Assets

9 Months Ended

Sep. 30, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

4.	Goodwill and Other Intangibles


	Mid-America		Southeast			West
	Group		Group			Group		Total
	(Dollars in Thousands)
Balance at January 1, 2018	$	281,403	$	50,346		$	1,828,541	$	2,160,290
Acquisitions		147,333		92,738			—		240,071
Divestitures		—		(927	)		—		(927	)
Balance at September 30, 2018	$	428,736	$	142,157		$	1,828,541	$	2,399,434

4.	Goodwill and Other Intangibles (continued)

Intangible assets subject to amortization consist of the following:

	Gross Amount		Accumulated Amortization			Net Balance
(Dollars in Thousands)	September 30, 2018
Noncompetition agreements	$	12,024	$	(11,105	)	$	919
Customer relationships		56,530		(18,325	)		38,205
Operating permits		458,952		(31,375	)		427,577
Use rights and other		19,564		(10,789	)		8,775
Trade names		12,800		(9,387	)		3,413
Total	$	559,870	$	(80,981	)	$	478,889

Intangible assets deemed to have an indefinite life and not being amortized consist of the following:

	Building Materials Business		Magnesia Specialties		Total
(Dollars in Thousands)	September 30, 2018
Operating permits	$	6,600	$	—	$	6,600
Use rights		20,642		—		20,642
Trade names		280		2,565		2,845
Total	$	27,522	$	2,565	$	30,087

Intangibles acquired during the year are as follows:

(Dollars in Thousands)	Amount		Weighted-average amortization period
Subject to amortization:
Customer relationships	$	20,620	12 years

Not subject to amortization:
Water rights		1,100	N/A
Total	$	21,720

4.	Goodwill and Other Intangibles (continued)

Total amortization expense for intangible assets for the nine-months ended September 30, 2018 and 2017 was $10,549,000 and $10,710,000, respectively.

The estimated amortization expense for intangible assets for the last three months of 2018 and for each of the next four years and thereafter is as follows:

(Dollars in Thousands)
October - December 2018	$	3,398
2019		13,429
2020		13,393
2021		12,703
2022		11,232
Thereafter		424,734
Total	$	478,889