Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Fixed assets (Schedule of Fixed Assets) (Details)

v3.8.0.1
Fixed assets (Schedule of Fixed Assets) (Details) - EUR (€)
€ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Disclosure of detailed information about property, plant and equipment [line items]    
Balance [1] € 73,274 € 72,564
Balance 78,837 73,274 [1]
Photovoltaic Plants [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 87,922  
Cost [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 93,171 88,049
Additions 10,081 5,122
Balance 103,252 93,171
Cost [Member] | Photovoltaic Plants [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 87,921 87,880
Additions 1 41
Balance 87,922 87,921
Cost [Member] | Biogas installation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 5,081
Additions 10,076 5,081
Balance 15,157 5,081
Cost [Member] | Office furniture and equipment [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 117 117
Additions 4
Balance 121 117
Cost [Member] | Leasehold Improvements [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 52 52
Additions
Balance 52 52
Depreciation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 19,897 15,485
Depreciation for the year 4,518 4,411
Effect of changes in exchange rates   1
Balance 24,415 19,897
Depreciation [Member] | Photovoltaic Plants [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 19,758 15,363
Depreciation for the year 4,396 4,394
Effect of changes in exchange rates   1
Balance 24,154 19,758
Depreciation [Member] | Biogas installation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance
Depreciation for the year 111
Effect of changes in exchange rates  
Balance 111
Depreciation [Member] | Office furniture and equipment [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 87 74
Depreciation for the year 11 13
Effect of changes in exchange rates  
Balance 98 87
Depreciation [Member] | Leasehold Improvements [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 52 48
Depreciation for the year 52 4
Effect of changes in exchange rates  
Balance 52 52
Carrying Amounts [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 73,274 72,564
Balance 78,837 73,274
Carrying Amounts [Member] | Photovoltaic Plants [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 68,163 72,517
Balance 63,768 68,163
Carrying Amounts [Member] | Biogas installation [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 5,081
Balance 15,046 5,081
Carrying Amounts [Member] | Office furniture and equipment [Member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 30 43
Balance 23 30
Carrying Amounts [Member] | Leasehold Improvements [member]    
Disclosure of detailed information about property, plant and equipment [line items]    
Balance 4
Balance
[1] Please refer to note 2C for functional and presentation currency.