Goodwill and Related Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

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):

	Residential Products		Industrial and Infrastructure Products		Renewable Energy and Conservation			Total
Balance at December 31, 2015	$	181,285	$	53,704	$	57,401		$	292,390
Acquired goodwill	—		—		12,283			12,283
Impairment	—		—		(929		)	(929		)
Foreign currency translation	—		180		108			288
Balance at December 31, 2016	$	181,285	$	53,884	$	68,863		$	304,032
Acquired goodwill	16,790		—		—			16,790
Adjustments to prior year acquisitions	—		—		(832		)	(832		)
Foreign currency translation	—		396		688			1,084
Balance at December 31, 2017	$	198,075	$	54,280	$	68,719		$	321,074

Schedule of Acquired Intangible Assets

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

	December 31, 2017				December 31, 2016
	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization		Estimated Useful Life
Indefinite-lived intangible assets:
Trademarks	$	45,107	$	—	$	44,720	$	—	Indefinite
Finite-lived intangible assets:
Trademarks	5,876		3,062		5,808		2,427		5 to 15 Years
Unpatented technology	28,107		12,033		26,720		10,041		5 to 20 Years
Customer relationships	80,707		39,652		78,569		33,585		5 to 17 Years
Non-compete agreements	1,649		931		1,649		623		4 to 10 Years
Backlog	—		—		900		900		.5 to 2 Years
	116,339		55,678		113,646		47,576
Total acquired intangible assets	$	161,446	$	55,678	$	158,366	$	47,576

Schedule of Acquired Intangible Asset Amortization Expense

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

	2017				2016				2015
	Indefinite-lived intangibles (1)		Definite-lived intangibles		Indefinite-lived intangibles (2)		Definite-lived intangibles (3)		Indefinite-lived intangibles (4)		Definite-lived intangibles
Residential Products	$	—	$	—	$	—	$	—	$	440	$	—
Industrial and Infrastructure Products	—		—		7,980		—		4,423		—
Renewable Energy and Conservation	247		—		1,068		198		—		—
Impairment charges	$	247	$	—	$	9,048	$	198	$	4,863	$	—

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

(2) Industrial and Infrastructure Products impairment charges due to discontinuation of U.S. bar grating product line and annual testing. Renewable Energy and Conservation impairment due to discontinuation of European residential solar racking business and annual testing.

(3) Renewable Energy and Conservation impairment due to discontinuation of European residential solar racking business.

(4) 2015 impairment charges recognized as a result of the Company’s annual impairment test of indefinite-lived intangibles.

Schedule of Intangible Assets Amortization Expense

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

	2017		2016		2015
Amortization expense	$	8,761	$	9,637	$	12,679

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):

	2018		2019		2020		2021		2022
Amortization expense	$	8,289	$	7,618	$	7,106	$	6,504	$	6,093