Debt And Financing Activities (Debt Covenants) (Narrative) (Details) (Maximum [Member])	Mar. 31, 2012
Maximum [Member]
Debt Instrument [Line Items]
Debt to capital ratio	56.5

Total Aggregate Indebtedness divided by Net Capital.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Rule 15c3

-Number 240

-Article 15c3

-Section 1

-Subsection a

-Paragraph 1

-Subparagraph i

Name:	us-gaap_RatioOfIndebtednessToNetCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant