Summary of Significant Accounting Policies - Summary of Non-current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Summary of non-current liabilities
Derivative instruments	$ 1,893	$ 576
Unrecognized tax benefits	4,811	2,878
Deferred rent	6,277	5,977
Retirement benefits	1,477	1,544
Other non-current liabilities	4,513	1,895
Non-current liabilities	$ 18,971	$ 12,870