Finance Receivables (Details 3) $ in Thousands	Dec. 31, 2015 USD ($) tenant	Dec. 31, 2014 USD ($) tenant
Credit Quality Of Finanace Receivables:
Financing receivable	$ 539,608	$ 519,425
Internally Assigned Grade 1 | Direct Financing Method
Credit Quality Of Finanace Receivables:
Number of tenants and obligors | tenant	0	0
Financing receivable	$ 0	$ 0
Internally Assigned Grade 2 | Direct Financing Method
Credit Quality Of Finanace Receivables:
Number of tenants and obligors | tenant	1	1
Financing receivable	$ 2,264	$ 2,259
Internally Assigned Grade 3 | Direct Financing Method
Credit Quality Of Finanace Receivables:
Number of tenants and obligors | tenant	11	9
Financing receivable	$ 429,212	$ 429,245
Internally Assigned Grade 4 | Direct Financing Method
Credit Quality Of Finanace Receivables:
Number of tenants and obligors | tenant	4	3
Financing receivable	$ 108,132	$ 87,921
Internally Assigned Grade 5 | Direct Financing Method
Credit Quality Of Finanace Receivables:
Number of tenants and obligors | tenant	0	0
Financing receivable	$ 0	$ 0