| Fair Value Measurements (Narrative) (Details) | 3 Months Ended | 
|---|---|
| Dec. 31, 2018  USD ($) | |
| Fair Value Measurements [Abstract] | |
| Transfers to level 1 | $ 0 | 
| Transfers to level 2 | 0 | 
| Transfers to Level 3 | $ 0 | 
| X | ||||||||||
| 
- References No definition available. 
 | 
| X | ||||||||||
| 
- Definition Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- Definition Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 |