Intangible Assets, Net - Net Consolidated Balance of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002
Accumulated Amortization	(18,335)
Total amortizable intangible assets	$ 6,667	$ 7,917
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life (In Years)	10 years
Gross Carrying Amount	$ 25,002
Accumulated Amortization	(18,335)
Total amortizable intangible assets	$ 6,667