Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2016

Goodwill And Intangible Assets Disclosure [Abstract]

The following table shows the changes in goodwill by reportable segment and in total. The information has been reclassified to conform to the presentation of the Corporation’s current reportable segments. For further information on the reorganization, please see Note O.

December 31	Mid- America Group			Southeast Group		West Group			Total
(add 000)	2016
Balance at beginning of period	$	281,403		$	50,346	$	1,736,486		$	2,068,235
Acquisitions		—			—		91,174			91,174
Divestitures		—			—		(72	)		(72	)
Balance at end of period	$	281,403		$	50,346	$	1,827,588		$	2,159,337

	2015
Balance at beginning of period	$	282,117		$	50,346	$	1,736,336		$	2,068,799
Acquisitions		—			—		8,464			8,464
Adjustments to purchase price allocations		—			—		(3,096	)		(3,096	)
Divestitures		(714	)		—		(5,218	)		(5,932	)
Balance at end of period	$	281,403		$	50,346	$	1,736,486		$	2,068,235

Intangible Assets Subject to Amortization

Intangible assets subject to amortization consist of the following:

December 31	Gross Amount		Accumulated Amortization			Net Balance
(add 000)	2016
Noncompetition agreements	$	6,274	$	(6,106	)	$	168
Customer relationships		45,755		(13,636	)		32,119
Operating permits		455,095		(19,493	)		435,602
Use rights and other		16,946		(9,239	)		7,707
Trade names		12,800		(5,681	)		7,119
Total	$	536,870	$	(54,155	)	$	482,715

	2015
Noncompetition agreements	$	6,274	$	(6,069	)	$	205
Customer relationships		35,805		(10,448	)		25,357
Operating permits		450,419		(12,294	)		438,125
Use rights and other		16,746		(8,030	)		8,716
Trade names		12,800		(3,408	)		9,392
Total	$	522,044	$	(40,249	)	$	481,795

Intangible Assets Deemed to Indefinite Life and Not Being Amortized

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

December 31	Building Materials Business		Magnesia Specialties		Total
(add 000)	2016
Operating permits	$	6,600	$	—	$	6,600
Use rights		19,152		—		19,152
Trade names		280		2,565		2,845
Total	$	26,032	$	2,565	$	28,597
	2015
Operating permits	$	6,600	$	—	$	6,600
Use rights		19,312		—		19,312
Trade names		280		2,565		2,845
Total	$	26,192	$	2,565	$	28,757

Schedule of Acquired Intangibles

During 2016, the Corporation acquired $15,134,000 of intangibles, consisting of the following:

(add 000, except year data)	Amount		Weighted-average amortization period
Subject to amortization:
Customer relationships	$	9,950	10.3 years
Operating permits		4,984	40.6 years
Other		200	1.5 years
Total	$	15,134	20.2 years

Estimated Amortization Expense of Intangible Assets

The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows:

(add 000)
2017	$	14,375
2018		13,417
2019		12,107
2020		11,727
2021		11,021
Thereafter		420,068
Total	$	482,715