Fair-Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Derivative [Line Items]
Interest income (expense), net	$ (3,569)	$ (3,977)
Interest Rate Swap
Derivative [Line Items]
Interest income (expense), net	1,700	500
Interest Rate Swap Buyouts
Derivative [Line Items]
Interest income (expense), net	$ 300	$ 100