Summary Of Significant Accounting Policies (Narrative) (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) segment property shares	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Common units in operating partnership | shares			7,305,355
Number of units in multi-family asset | property			395
Allowance for uncollectible accounts	$ 400,000		$ 400,000		$ 400,000
Allowance for uncollectable deferred rent receivables	914,000		$ 914,000		876,000
Cash and cash equivalents maximum benchmark (in months)			3 months
Minimum expected future benefit period on expenditures cost to be capitalized and depreciated (in years)			2 years
Minimum expected future benefit period on transaction cost to be capitalized and depreciated (in years)			1 year
Length of time criteria for expected sale of assets to be classified as properties held for disposition			12 months
Below market lease, net	1,700,000		$ 1,700,000		1,800,000
Below market leases, accumulated amortization	11,100,000		11,100,000		10,800,000
Impairment on assets			0	$ 0
Income tax expense			0
Tax benefit for uncertain tax positions			$ 0		0
Number of operating segments | segment			2
Number of reportable segments | segment			1
Cost of operations	31,460,000	$ 30,796,000	$ 65,053,000	63,252,000
General and administrative expenses	2,827,000	2,828,000	6,060,000	5,678,000
Net real estate investment property	1,808,573,000		1,808,573,000		1,822,390,000
Properties held for sale, net	124,680,000		124,680,000		128,093,000
Rental income	107,782,000	101,824,000	215,607,000	205,583,000
Rental income, operating leases	83,800,000	78,800,000	166,600,000	159,400,000
Rental income, variable lease payments	24,000,000.0	23,000,000.0	49,000,000.0	46,200,000
Operating lease, right-of-use asset	1,700,000		1,700,000
Operating lease, liability	$ 1,700,000		$ 1,700,000
Operating lease, discount rate	4.20%		4.20%
Reclassification [Member]
Summary Of Significant Accounting Policies [Line Items]
Net real estate investment property					(128,100,000)
Properties held for sale, net					128,100,000
Divisional Vice President [Member] | Reclassification [Member]
Summary Of Significant Accounting Policies [Line Items]
Cost of operations		(460,000)		(1,000,000.0)
General and administrative expenses		$ 460,000		$ 1,000,000.0
Above Market Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible assets, net	$ 1,500,000		$ 1,500,000		1,800,000
Finite-lived intangible assets, accumulated amortization	(10,300,000)		(10,300,000)		(10,000,000.0)
Acquired In Place Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible assets, net	4,100,000		4,100,000		4,700,000
Finite-lived intangible assets, accumulated amortization	$ 2,400,000		$ 2,400,000		1,300,000
JV Partner [Member]
Summary Of Significant Accounting Policies [Line Items]
Consolidated entity ownership percentage	5.00%		5.00%
Buildings And Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Net real estate investment property	$ 2,171,281,000		$ 2,171,281,000		2,157,407,000
Buildings And Improvements [Member] | Reclassification [Member]
Summary Of Significant Accounting Policies [Line Items]
Net real estate investment property					(217,500,000)
Properties held for sale, net					$ 217,500,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			5 years
Operating lease, expiration date			Sep. 30, 2029
Operating lease, remaining lease term	10 years 3 months 18 days		10 years 3 months 18 days
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)			30 years
Operating lease, expiration date			Jan. 31, 2030
Operating lease, remaining lease term	10 years 7 months 6 days		10 years 7 months 6 days