Significant Accounting Policies (Estimated Useful Lives Of Assets) (Details) |
3 Months Ended |
|---|---|
Mar. 31, 2018 | |
| Minimum [Member] | Buildings And Improvements [Member] | |
| Property, Plant and Equipment [Line Items] | |
| Estimated useful lives of assets | 5 years |
| Minimum [Member] | Furniture, Fixtures And Equipment [Member] | |
| Property, Plant and Equipment [Line Items] | |
| Estimated useful lives of assets | 5 years |
| Maximum [Member] | Buildings And Improvements [Member] | |
| Property, Plant and Equipment [Line Items] | |
| Estimated useful lives of assets | 40 years |
| Maximum [Member] | Furniture, Fixtures And Equipment [Member] | |
| Property, Plant and Equipment [Line Items] | |
| Estimated useful lives of assets | 10 years |