Intangibles - Intangible Assets Other Than Goodwill and Trade Names (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization	$ 571,608	$ 601,013
Patents And Other
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization	16,459	17,554
Intangible assets, accumulated amortization	42,395	43,021
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Intangible assets, net of accumulated amortization	555,149	583,459
Intangible assets, accumulated amortization	$ 142,623	$ 126,824