Summary of Significant Accounting Policies (Deferred Financing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deferred financing costs	$ 11,488	$ 11,530
Accumulated amortization	(4,335)	(3,859)
Deferred financing costs, net	7,153	7,671
Fixed debt arrangements
Deferred financing costs	14,641	14,501
Accumulated amortization	(3,446)	(2,944)
Deferred financing costs, net	$ 11,195	$ 11,557