International Retirement Plan (Components of Net Periodic Benefit Costs and Other Amounts Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 204	$ 166	$ 155
Interest cost	84	151	148
Amortization of actuarial loss	351	200	177
Total net periodic pension cost	639	517	480
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	(1,223)	1,815	453
Amortization of prior years' unrecognized loss	(351)	(200)	(177)
Tax (benefit) provision	791	(555)	(88)
Total recognized as accumulated other comprehensive income (loss)	(783)	1,060	188
Total expense recognized in net periodic benefit cost and other comprehensive income	$ (144)	$ 1,577	$ 668