Shareholders' Equity Changes in Accumulated Other Comprehensive Income (Loss) Balances (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2016			$ (83,837)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(2,171)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	$ 17,020	$ (10,904)	30,436	$ (1,038)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			31,566
Balance as of June 30, 2017	(54,442)		(54,442)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2016			(84,133)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax			30,436
Balance as of June 30, 2017	(53,697)		(53,697)
Cash Flow Hedging | Foreign Exchange Contract
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2016			296
Reclassification to the income statement			(2,171)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			1,130
Balance as of June 30, 2017	$ (745)		$ (745)