Summary of Significant Accounting Policies (Supplemental Consolidated Statements of Cash Flows Information) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Supplemental disclosure of cash activities:
Cash paid for interest	$ 10,547,000	$ 11,669,000
Supplemental disclosure of non-cash activities:
Capitalization of interest and financing costs	1,555,000	1,224,000
Buildings and improvements included in accounts payable and accrued liabilities	$ 1,224,000
Recognition of right-of-use assets and related lease liabilities		$ 703,000