Shareholders' Equity Changes in Accumulated Other Comprehensive Income (Loss) Balances (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2017			$ (45,629)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(2,486)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	$ (24,881)	$ 17,020	(13,903)	$ 30,436
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(6,178)
Balance as of June 30, 2018	(54,293)		(54,293)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2017			(42,442)
Balance as of June 30, 2018	(56,345)		(56,345)
Cash Flow Hedging | Foreign Exchange Contract
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2017			(34)
Reclassification to the statement of income			(2,616)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			7,725
Balance as of June 30, 2018	5,075		5,075
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2017			(3,153)
Reclassification to the statement of income			130
Balance as of June 30, 2018	$ (3,023)		$ (3,023)