Summary of Significant Accounting Policies (Supplemental Consolidated Statements of Cash Flows Information) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental disclosure of cash activities:
Cash paid for interest	$ 5,271,000	$ 5,653,000
Supplemental disclosure of non-cash activities:
Capitalization of interest and financing costs	799,000	593,000
Buildings and improvements included in accounts payable and accrued liabilities	$ 644,000
Recognition of right-of-use assets and related lease liabilities		$ 703,000