Condensed Consolidating Financial Information (Narrative) (Details)	6 Months Ended
Jun. 30, 2018
Condensed Consolidating Financial Information [Abstract]
Subsidiary ownership	100.00%

Percentage of subsidiary's or equity method investee's stock owned by parent immediately after all stock transactions.

No definition available.

Name:	us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration