Other Assets - Summary of Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Restricted cash and cash equivalents	$ 1,255	$ 1,289
Pension asset	2,593	1,037
Other	995	950
Total	$ 4,843	$ 3,276