Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Indefinite-lived trade name	$ 2,537	$ 0
Akers AB [Member]
Goodwill [Line Items]
Indefinite-lived trade name	2,537
Estimated future amortization expense in 2017	1,150
Estimated future amortization expense in 2018	1,150
Estimated future amortization expense in 2019	1,150
Estimated future amortization expense in 2020	1,150
Estimated future amortization expense in 2021	485
Estimated future amortization expense, thereafter	$ 3,979