Borrowings (Bank Of America Line Of Credit) (Narrative) (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	Aug. 07, 2020	Aug. 08, 2019	Oct. 31, 2016	Dec. 31, 2020	Dec. 31, 2019	Mar. 06, 2020
Debt Instrument [Line Items]
Contractual facility				$ 300,449	$ 283,138
Bank Of America Line Of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, previous borrowing capacity						$ 5,000
Maturity date		Sep. 01, 2020	Oct. 31, 2019	Mar. 06, 2023	Mar. 06, 2023
Contractual facility			$ 5,000	$ 5,000	$ 5,000
Extension period		10 months
Floor Rate [Member] | Bank Of America Line Of Credit [Member]
Debt Instrument [Line Items]
Spread over LIBOR	1.00%