Risk Management and Use of Derivative Financial Instruments - Narratives (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative
Collateral posted	$ 0	$ 0
Interest expense	39,902,000	40,226,000	$ 35,824,000
Estimated amount of derivative income to be classified from OCI to income	100,000
Maximum credit exposure	0
Derivatives in net liability position	0	0
Single counterparty
Derivative
Maximum credit exposure	200,000
AOCI Including Portion Attributable to Noncontrolling Interest
Derivative
Other comprehensive (loss) income before reclassifications	(335,000)	544,000	265,000
AOCI Including Portion Attributable to Noncontrolling Interest | Reclassification out of Accumulated Other Comprehensive Income
Derivative
Interest expense	$ (1,004,000)	$ (715,000)	$ 219,000