Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Changes in Goodwill

The following table shows the changes in goodwill by reportable segment and in total:

December 31	East Group			West Group			Total
(in millions)	2020
Balance at beginning of period	$	574.3		$	1,822.5		$	2,396.8
Acquisitions		—			17.3			17.3
Goodwill reclassified from/(allocated to) assets held for sale		0.1			(0.1	)		—
Divestitures		—			(0.1	)		(0.1	)
Transfer of operations from East Group to West Group		(1.9	)		1.9			—
Balance at end of period	$	572.5		$	1,841.5		$	2,414.0
	2019
Balance at beginning of period	$	576.1		$	1,823.0		$	2,399.1
Measurement period adjustments		(1.6	)		—			(1.6	)
Goodwill allocated to assets held for sale		(0.2	)		—			(0.2	)
Divestitures		—			(0.5	)		(0.5	)
Balance at end of period	$	574.3		$	1,822.5		$	2,396.8

Intangible Assets Subject to Amortization

Intangible assets subject to amortization consist of the following:

December 31	Gross Amount		Accumulated Amortization			Net Balance
(in millions)	2020
Noncompetition agreements	$	4.2	$	(4.1	)	$	0.1
Customer relationships		91.3		(35.6	)		55.7
Operating permits		460.8		(48.4	)		412.4
Use rights and other		16.3		(13.0	)		3.3
Trade names		12.8		(12.3	)		0.5
Total	$	585.4	$	(113.4	)	$	472.0
	2019
Noncompetition agreements	$	6.3	$	(6.2	)	$	0.1
Customer relationships		65.6		(30.4	)		35.2
Operating permits		459.0		(42.3	)		416.7
Use rights and other		16.7		(12.1	)		4.6
Trade names		12.8		(10.9	)		1.9
Total	$	560.4	$	(101.9	)	$	458.5

Intangible Assets Deemed to Indefinite Life that are Therefore Not Amortized

Intangible assets deemed to have an indefinite life that are therefore not amortized consist of the following:

December 31	Building Materials Business		Magnesia Specialties		Total
(in millions)	2020
Operating permits	$	6.6	$	—	$	6.6
Use rights		26.7		—		26.7
Trade names		0.2		2.5		2.7
Total	$	33.5	$	2.5	$	36.0
	2019
Operating permits	$	6.6	$	—	$	6.6
Use rights		19.0		—		19.0
Trade names		0.2		2.5		2.7
Total	$	25.8	$	2.5	$	28.3

Summary of Intangible Assets Acquired

During 2020, the Company acquired $35.2 million of intangible assets, consisting of the following:

(in millions, except year data)	Amount		Weighted-average amortization period
Subject to amortization:
Customer relationships	$	25.8	15 years
Operating permits		1.9	35 years
Total subject to amortization	$	27.7	16 years
Not subject to amortization:
Use Rights	$	7.5	N/A
Total	$	35.2

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:

(in millions)
2021	$	14.1
2022		12.9
2023		12.5
2024		12.3
2025		12.2
Thereafter		408.0
Total	$	472.0