Amount of gain (loss) on termination of lease before expiration of lease term.

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Amount of the adjustment to rental revenues to measure escalating leasing revenues on a straight line basis.

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Revenues (Narrative) (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
Revenues (Narrative) (Details) - USD ($)	Apr. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Lessor Lease Description [Line Items]
Payment accepted on termination of lease prior to contractual expiration	$ 4,300,000
Total revenues		$ 36,170,000	$ 36,398,000	$ 115,088,000	$ 108,871,000
Contract Termination [Member]
Lessor Lease Description [Line Items]
Total revenues				5,400,000
Cash payment reduced by straight line rent receivable				500,000
Accelerated Intangible Lease Liability Amortization [Member] \| Contract Termination [Member]
Lessor Lease Description [Line Items]
Total revenues				1,500,000
Other Income [Member] \| Contract Termination [Member]
Lessor Lease Description [Line Items]
Total revenues				$ 3,800,000