International Retirement Plan (Summary of Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Other assets	$ 3,844	$ 3,343
Accrued liabilities	(163)	(140)
Other liabilities	(10,228)	(10,357)
Net liability	$ (6,547)	$ (7,154)