Fair Value Measurement (Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets
Cash equivalents	$ 140,037	$ 107,494
Marketable securities	9,019	62,442
Derivatives	473	667
Interest rate swap contracts
Liabilities
Derivatives	1,195	2,403
Foreign currency derivatives
Liabilities
Derivatives	2,948	3,515
Level I
Assets
Cash equivalents	140,037	107,494
Marketable securities	9,019	62,442
Derivatives	0	0
Level I | Interest rate swap contracts
Liabilities
Derivatives	0	0
Level I | Foreign currency derivatives
Liabilities
Derivatives	0	0
Level II
Assets
Cash equivalents	0	0
Marketable securities	0	0
Derivatives	473	667
Level II | Interest rate swap contracts
Liabilities
Derivatives	1,195	2,403
Level II | Foreign currency derivatives
Liabilities
Derivatives	2,948	3,515
Level III
Assets
Cash equivalents	0	0
Marketable securities	0	0
Derivatives	0	0
Level III | Interest rate swap contracts
Liabilities
Derivatives	0	0
Level III | Foreign currency derivatives
Liabilities
Derivatives	$ 0	$ 0