Accumulated Other Comprehensive Income (Amounts Reclassified from AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income [Line Items]
Nonoperating Income (Expense)	$ (3,993)	$ (12,029)	$ (3,592)	$ (25,835)
Interest Rate Swap | Reclassification out of Accumulated Other Comprehensive Income | Derivative Instruments
Accumulated Other Comprehensive Income [Line Items]
Interest Expense - Amortization of Derivative Instruments	103	24	205	48
Interest Expense - Settlement Payments	1,706	(550)	2,088	(1,126)
Nonoperating Income (Expense)	$ 1,809	$ (526)	$ 2,293	$ (1,078)