Summary Of Significant Accounting Policies (Narrative) (Details) $ in Thousands, ft² in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) ft² customer	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) ft² customer	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Significant Accounting Policies [Line Items]
Square footage of operating properties (in square feet) | ft²	29.7		29.7
Accrued Rent, Accrued Contract Receivables and Accounts Receivable, net	$ 70,039		$ 70,039		$ 81,016
Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Significant Accounting Policies [Line Items]
Cash flow hedge gain (loss) to be amortized within 12 months	$ 900		$ 900
Tenant Base [Member] | Revenue Benchmark [Member]
Significant Accounting Policies [Line Items]
Number of customers | customer	2		2
HOUSTON | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk			24.30%
OTHER PARTS OF TEXAS | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk			7.90%
FLORIDA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	19.70%
CALIFORNIA | Geographic Concentration Risk [Member] | Revenue Benchmark [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk	15.90%
Largest Two Customers Each | Tenant Base [Member] | Revenue Benchmark [Member]
Significant Accounting Policies [Line Items]
Concentrations of risk			2.60%
COVID-19 [Member]
Significant Accounting Policies [Line Items]
Net recoveries of adjustments to revenue related to potentially uncollectible revenues and disputed amounts	$ 1,200		$ 2,900
Adjustment to revenue related to potentially uncollectible revenues and disputed amounts		$ 19,300		$ 28,700
Accrued Rent, Accrued Contract Receivables and Accounts Receivable, net	5,000		5,000		$ 9,600
Rent forgiveness	1,500	300	3,500	300
Straight Line Rent Receivables [Member]
Significant Accounting Policies [Line Items]
Adjustment to revenue related to potentially uncollectible revenues and disputed amounts		$ 4,800		$ 12,400
Cash Basis Tenants [Member]
Significant Accounting Policies [Line Items]
Rent forgiveness	$ 1,300		$ 2,800