Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

General (Details) $ in Thousands	3 Months Ended	9 Months Ended
General (Details) $ in Thousands	Sep. 30, 2017 USD ($)	Sep. 30, 2018 item	Sep. 30, 2017 USD ($)
General
Number of electric distribution cooperative members \| item		38
ASU 2014-09
General
Refund liability adjustment \| $	$ 9,250		$ 15,000