Goodwill and Related Intangible Assets

9 Months Ended

Sep. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

The changes in the carrying amount of goodwill for the nine months ended September 30, 2019 are as follows (in thousands):



	Renewable Energy & Conservation			Residential Products		Industrial and Infrastructure Products		Total
Balance at December 31, 2018	$	71,827		$	198,075	$	53,769	$	323,671
Acquired goodwill	4,185			—				4,185
Adjustments to prior year acquisitions	(172		)			—		(172		)
Foreign currency translation	137			—		162		299
Balance at September 30, 2019	$	75,977		$	198,075	$	53,931	$	327,983

Acquired Intangible Assets

Acquired intangible assets consist of the following (in thousands):



	September 30, 2019				December 31, 2018
	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization		Weighted-Average Amortization Period
Indefinite-lived intangible assets:
Trademarks	$	44,770	$	—	$	43,870	$	—	Indefinite
Finite-lived intangible assets:
Trademarks	6,122		3,954		6,094		3,518		3 to 15 Years
Unpatented technology	29,444		15,301		28,644		13,881		5 to 20 Years
Customer relationships	74,072		39,187		70,419		35,678		5 to 17 Years
Non-compete agreements	1,649		1,430		1,649		1,224		4 to 10 Years
	111,287		59,872		106,806		54,301
Total acquired intangible assets	$	156,057	$	59,872	$	150,676	$	54,301

The following table summarizes the acquired intangible asset amortization expense for the three and nine months ended September 30 (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Amortization expense	$	1,840	$	2,121	$	5,434	$	6,408

Amortization expense related to acquired intangible assets for the remainder of fiscal 2019 and the next five years thereafter is estimated as follows (in thousands):



	2019		2020		2021		2022		2023		2024
Amortization expense	$	1,798	$	6,904	$	6,709	$	6,231	$	5,693	$	5,437