Summary of Operations and Significant Accounting Policies - Component of Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Translation adjustment	$ (36,164)	$ (16,357)
Unrealized loss on defined benefit plan	(31,320)	(35,719)
Unrealized foreign currency losses	$ (16,932)	$ (16,326)