| de | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| de | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| fr | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| fr | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| el | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| el | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| es | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| es | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| et | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| et | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| fi | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| fi | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| it | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| it | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| lt | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| lt | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| lv | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| lv | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| nl | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| nl | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| si | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| si | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| sk | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| sk | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| en | http://www.xbrl.org/2010/role/message |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |
| en | http://www.xbrl.org/2010/role/terseMessage |
| srf_v0068: '2C1'={$c} must be greater than zero if '2C2'= {$a} + '2C3'={$b} is greater than zero |