Annual report pursuant to Section 13 and 15(d)

Intangible Assets (Narrative) (Detail)

v3.8.0.1
Intangible Assets (Narrative) (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]      
Amortization of intangible assets $ 21,327 $ 20,703 $ 20,650
Estimated useful life 8 years 9 months 27 days