Mortgage And Other Notes Receivable Mortgage and Other Notes Receivable (Schedule of Bickford Construction Loans) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Commitments, Fixed Rates	$ 311,700,000
Loans and Leases Receivable, Net Amount	(246,111,000)	$ (141,486,000)
Bickford Note Investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Commitments, Fixed Rates	56,700,000
Loans and Leases Receivable, Net Amount	$ (32,471,000)
July 2016 [Member] | Bickford Note Investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Note Receivable Interest Rate	9.00%
Loan Term	5 years
Loans and Leases Receivable, Commitments, Fixed Rates	$ 14,000,000
Loans and Leases Receivable, Net Amount	$ (13,047,000)
January 2017 [Member] | Bickford Note Investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Note Receivable Interest Rate	9.00%
Loan Term	5 years
Loans and Leases Receivable, Commitments, Fixed Rates	$ 14,000,000
Loans and Leases Receivable, Net Amount	$ (11,931,000)
January 2018 [Member] | Bickford Note Investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Note Receivable Interest Rate	9.00%
Loan Term	5 years
Loans and Leases Receivable, Commitments, Fixed Rates	$ 14,000,000
Loans and Leases Receivable, Net Amount	$ (4,515,000)
July 2018 [Member] | Bickford Note Investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Note Receivable Interest Rate	9.00%
Loan Term	5 years
Loans and Leases Receivable, Commitments, Fixed Rates	$ 14,700,000
Loans and Leases Receivable, Net Amount	$ (2,978,000)