Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Stockholders Equity [Abstract]
Foreign currency translation adjustments, income tax effect	$ 6,824
Amortization of terminated hedge, income tax effect			$ 60
Unrealized loss on marketable security, income tax effect		$ (809)	(831)
Unrealized derivative gains and losses on cash flow hedges, income tax effect	667	2,490	536
Minimum pension liability, income tax effect	(1,650)	$ (983)	$ (5,003)
Cumulative-effect adjustment due to adoption of ASU 2016-01, income tax effect	$ 1,045