Shareholders' Equity Changes in Accumulated Other Comprehensive Income (Loss) Balances (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 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	(40)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	10,978	$ 13,416
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	15,632
Balance as of March 31, 2018	(30,037)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 31, 2017	(42,442)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	10,978
Balance as of March 31, 2018	(31,464)
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	(125)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	4,654
Balance as of March 31, 2018	4,495
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	85
Balance as of March 31, 2018	$ (3,068)