Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Intangible Assets [Line Items]
Gross Carrying Value	$ 157,881	$ 158,236
Gross Carrying Value	158,581	158,936
Accumulated Amortization	(25,933)	(23,498)
Accumulated Amortization	(25,933)	(23,498)
Net Carrying Value	131,948	134,738
Net Carrying Value	$ 132,648	$ 135,438
Weighted Average Useful Life (in years)	16 years	16 years
Trademark
Intangible Assets [Line Items]
Gross Carrying Value	$ 700	$ 700
Net Carrying Value	700	700
Technology - developed
Intangible Assets [Line Items]
Gross Carrying Value	53,252	53,315
Accumulated Amortization	(6,625)	(5,942)
Net Carrying Value	$ 46,627	$ 47,373
Weighted Average Useful Life (in years)	19 years	19 years
Patents
Intangible Assets [Line Items]
Gross Carrying Value	$ 240	$ 240
Accumulated Amortization	(240)	$ (240)
Net Carrying Value	$ 0
Weighted Average Useful Life (in years)	8 years	8 years
Customer relationships
Intangible Assets [Line Items]
Gross Carrying Value	$ 101,170	$ 101,460
Accumulated Amortization	(18,253)	(16,609)
Net Carrying Value	$ 82,917	$ 84,851
Weighted Average Useful Life (in years)	14 years	14 years
Trademark
Intangible Assets [Line Items]
Gross Carrying Value	$ 2,160	$ 2,160
Accumulated Amortization	(188)	(159)
Net Carrying Value	$ 1,972	$ 2,001
Weighted Average Useful Life (in years)	20 years	20 years
Other intangibles
Intangible Assets [Line Items]
Gross Carrying Value	$ 1,059	$ 1,061
Accumulated Amortization	(627)	(548)
Net Carrying Value	$ 432	$ 513
Weighted Average Useful Life (in years)	3 years	3 years