XML 67 R54.htm IDEA: XBRL DOCUMENT v3.8.0.1
Other Intangibles - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Intangible Liability Disclosure [Abstract]    
Amortization expense $ 0.3 $ 2.7