Summary of Significant Accounting Policies (Details) - USD ($) |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|
| Summary of Significant Accounting Policies [Abstract] | |||
| Restricted cash | $ 7,558,000 | $ 7,557,000 | $ 7,557,000 |
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|