Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Gross Carrying Amount	$ 157,413	$ 158,084
Accumulated Amortization	$ (20,879)	$ (13,331)
Weighted Average Useful Life (in years)	16 years	16 years
Trademark
Intangible Assets [Line Items]
Gross Carrying Amount, indefinite lived intangible assets	$ 700	$ 700
Technology - developed
Intangible Assets [Line Items]
Gross Carrying Amount	51,689	51,801
Accumulated Amortization	$ (5,221)	$ (3,201)
Weighted Average Useful Life (in years)	19 years	19 years
Patents
Intangible Assets [Line Items]
Gross Carrying Amount	$ 240	$ 240
Accumulated Amortization	$ (240)	$ (238)
Weighted Average Useful Life (in years)	8 years	8 years
Customer relationships
Intangible Assets [Line Items]
Gross Carrying Amount	$ 101,563	$ 102,120
Accumulated Amortization	$ (14,821)	$ (9,636)
Weighted Average Useful Life (in years)	14 years	14 years
Other intangibles
Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,061	$ 1,063
Accumulated Amortization	$ (466)	$ (209)
Weighted Average Useful Life (in years)	3 years	3 years
Trademark
Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,160	$ 2,160
Accumulated Amortization	$ (131)	$ (47)
Weighted Average Useful Life (in years)	20 years	20 years