Summary of Significant Accounting Policies (Deferred Financing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred financing costs	$ 13,786	$ 13,776
Accumulated amortization	(7,752)	(5,743)
Deferred financing costs, net	6,034	8,033
Fixed debt arrangements
Deferred financing costs	19,327	15,777
Accumulated amortization	(4,765)	(4,937)
Deferred financing costs, net	$ 14,562	$ 10,840