Goodwill and Related Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Carrying Amount of Goodwill

The changes in the carrying amount of goodwill for the years ended December 31 were as follows (in thousands):

	Renewable Energy & Conservation			Residential Products		Industrial and Infrastructure Products			Total
Balance at December 31, 2017	$	68,719		$	198,075	$	54,280		$	321,074
Acquired goodwill	3,051			—		—			3,051
Adjustments to prior year acquisitions	—			—		(38		)	(38		)
Foreign currency translation	57			—		(473		)	(416		)
Balance at December 31, 2018	$	71,827		$	198,075	$	53,769		$	323,671
Acquired goodwill	5,857			—		—			5,857
Adjustments to prior year acquisitions	(172		)	—		—			(172		)
Foreign currency translation	90			—		259			349
Balance at December 31, 2019	$	77,602		$	198,075	$	54,028		$	329,705

Schedule of Acquired Intangible Assets

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

	December 31, 2019				December 31, 2018
	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization		Estimated Useful Life
Indefinite-lived intangible assets:
Trademarks	$	45,770	$	—	$	43,870	$	—	Indefinite
Finite-lived intangible assets:
Trademarks	6,139		4,105		6,094		3,518		3 to 15 Years
Unpatented technology	29,544		15,807		28,644		13,881		5 to 20 Years
Customer relationships	71,195		40,294		70,419		35,678		5 to 17 Years
Non-compete agreements	1,649		1,499		1,649		1,224		4 to 10 Years
	108,527		61,705		106,806		54,301
Total acquired intangible assets	$	154,297	$	61,705	$	150,676	$	54,301

Schedule of Acquired Intangible Asset Amortization Expense

The following table summarizes the impairment charges for the years ended December 31 (in thousands):

	2019				2018				2017
	Indefinite-lived intangibles		Definite-lived intangibles		Indefinite-lived intangibles (1)		Definite-lived intangibles (2)		Indefinite-lived intangibles (3)		Definite-lived intangibles
Renewable Energy and Conservation	$	—	$	—	$	1,037	$	315	$	247	$	—
Residential Products	—		—		200		—		—		—
Industrial and Infrastructure Products	—		—		—		—		—		—
Impairment charges	$	—	$	—	$	1,237	$	315	$	247	$	—

(1) Residential Products impairment charges due to annual testing. Renewable Energy and Conservation impairment charges due to the annual testing in its international solar racking business and restructuring in its domestic greenhouse business.

(2) Renewable Energy and Conservation impairment charges due to the restructuring in its domestic greenhouse business.

(3) Renewable Energy and Conservation impairment charges due to the discontinuation of its domestic greenhouse business in China.

Schedule of Intangible Assets Amortization Expense

The following table summarizes amortization expense for the years ended December 31 (in thousands):

	2019		2018		2017
Amortization expense	$	7,271	$	8,222	$	8,761

Schedule of Amortization Expense

Amortization expense related to acquired intangible assets for the next five years ended December 31 is estimated as follows (in thousands):

	2020		2021		2022		2023		2024
Amortization expense	$	7,133	$	6,938	$	6,460	$	5,922	$	5,666