Shareholders' Equity (Schedule Of Dividends) (Parenthetical) (Details)	6 Months Ended
Jun. 30, 2018
Series B [Member]
Class Of Stock [Line Items]
Dividend rate percentage	7.25%
Series C Preferred Stock [Member]
Class Of Stock [Line Items]
Dividend rate percentage	6.50%

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