Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Stockholders Equity [Abstract]
Cumulative-effect adjustment due to adoption of ASU 2016-01, income tax effect			$ 1,045
Foreign currency translation adjustments, income tax effect	$ 749	$ 3,693	6,824
Unrealized derivative gains on cash flow hedges, income tax effect	928	928	667
Minimum pension liability, income tax effect	$ (1,071)	$ (2,048)	$ (1,650)