Investments in Unconsolidated Companies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) entities	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) entities
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated joint ventures in which equity interests held | entities	9
Equity in earnings of unconsolidated joint ventures	$ 31,406	$ 21,444	$ 63,310
Impairment charges	$ 0	$ 0	$ 4,481
Medical Office Portfolio Sale [Member]
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated joint ventures in which equity interests held | entities			2
Equity in earnings of unconsolidated joint ventures			$ 47,500