Summary of Significant Accounting Policies - Summary of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Cumulative currency translation adjustments	$ (68,063)	$ (55,553)
Unrealized gain on cash flow hedges, net of taxes of $662 and $603	824	872
Retirement benefits, net of taxes of ($201) and ($277)	(86)	(828)
Accumulated other comprehensive loss	(67,325)	(55,509)
Unrealized gain / (loss) on cash flow hedges, taxes	662	603
Retirement benefits, taxes	$ (201)	$ (277)