Basis Of Presentation And Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended				24 Months Ended
	Dec. 31, 2021 USD ($) segment property shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2021 USD ($) customer	Aug. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Common units in operating partnership | shares	7,305,355
Land and building held for development, net	$ 78,990,000	$ 37,922,000			$ 78,990,000
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
Below market lease, net	$ 2,800,000	2,200,000			2,800,000
Below market leases, accumulated amortization	13,100,000	12,200,000			13,100,000
Impairment on assets		0	$ 0	$ 0
Operating lease, right-of-use asset	$ 1,300,000	$ 1,500,000			$ 1,300,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets			Other Assets
Operating lease, liability	$ 1,300,000	$ 1,500,000			$ 1,300,000
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities			Accounts Payable and Accrued Liabilities
Accumulated amortization	$ 300,000	$ 200,000			$ 300,000
Accounts receivable, write-off	100,000	1,600,000	1,100,000
Deferred rent receivable, write-off	300,000	3,100,000	500,000
Rental income	438,703,000	415,623,000	429,846,000
Rental income, operating leases	333,900,000	319,200,000	333,300,000
Rental income, variable lease payments	104,800,000	96,400,000	$ 96,500,000
Income tax expense	0
Tax benefit for uncertain tax positions	$ 0	0
Number of operating segments | segment	2
Number of reportable segments | segment	1
Deferred rent receivable		5,700,000
Rent receivable abated	$ 300,000
Gross real estate investment property	3,106,482,000	2,924,660,000			3,106,482,000
Properties held for sale, net	33,609,000	75,138,000			$ 33,609,000
Reclassification [Member]
Summary Of Significant Accounting Policies [Line Items]
Land and building held for development, net		(5,100,000)
Gross real estate investment property		(70,000,000.0)
Properties held for sale, net		75,100,000
COVID-19 [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferral agreement, number of customers | customer					317
Deferral agreement, percentage of customers on a percentage of total rental income basis					9.50%
Deferred rent receivable	500,000				$ 6,200,000
Rent receivable abated		1,300,000			1,600,000
Deferred payments received					$ 5,300,000
Collection rate percentage on deferral repayments					99.80%
Deferred payments to be repaid thereafter					$ 900,000
Above Market Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible assets, net	600,000	1,200,000			600,000
Finite-lived intangible assets, accumulated amortization	(11,600,000)	(11,100,000)			(11,600,000)
Acquired In Place Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible assets, net	6,000,000.0	5,300,000			6,000,000.0
Finite-lived intangible assets, accumulated amortization	$ 10,500,000	7,200,000			$ 10,500,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	5 years
Operating lease, expiration date	2029
Operating lease, remaining lease term	7 years 9 months 18 days
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	30 years
Operating lease, expiration date	2030
Operating lease, remaining lease term	8 years 1 month 6 days
Highgate at the Mile [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of units developed | property	395
Highgate at the Mile [Member] | JV Partner [Member]
Summary Of Significant Accounting Policies [Line Items]
Consolidated entity ownership percentage	5.00%				5.00%
Brentford at The Mile [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of units developed | property	411
Gross real estate investment property	$ 5,100,000				$ 5,100,000	$ 5,100,000
Brentford at The Mile [Member] | JV Partner [Member]
Summary Of Significant Accounting Policies [Line Items]
Consolidated entity ownership percentage	1.80%				1.80%
Investment in Joint Venture [Member] | Highgate at the Mile [Member]
Summary Of Significant Accounting Policies [Line Items]
Consolidated entity ownership percentage	95.00%				95.00%
Investment in Joint Venture [Member] | Brentford at The Mile [Member]
Summary Of Significant Accounting Policies [Line Items]
Consolidated entity ownership percentage	98.20%				98.20%
Land and building held for development, net	$ 59,900,000	$ 15,100,000			$ 59,900,000