Summary of Significant Accounting Policies (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite Lived Intangible Assets [Line Items]
Earnout liability outstanding	$ 0	$ 0	$ 0
Provision for asset impairment	0	0	4,420,000
Depreciation expense	37,806,000	37,495,000	39,304,000
Amortization of leasing fees	731,000	615,000	$ 546,000
COVID-19 [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Deferred rent receivable	$ 399,000	$ 4,457,000