Intangible Assets - Amortized Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 60,724	$ 60,724
Accumulated Amortization	50,611	47,535
Net Carrying Value	10,113	13,189
Distribution Networks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	38,060	38,060
Accumulated Amortization	38,060	38,060
Net Carrying Value	0	0
Completed Technologies [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	13,687	13,687
Accumulated Amortization	6,619	4,181
Net Carrying Value	7,068	9,506
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	8,607	8,607
Accumulated Amortization	5,716	5,202
Net Carrying Value	2,891	3,405
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	370
Accumulated Amortization	216
Net Carrying Value	$ 154
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value		370
Accumulated Amortization		92
Net Carrying Value		$ 278