Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical)	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Percentage of dividend on convertible preferred stock	1.50%	1.50%	1.50%	1.50%
Series G 1.5% Convertible Preferred Stock [Member]
Percentage of dividend on convertible preferred stock			1.50%

The percentage rate used to calculate dividend payments on preferred stock.

No definition available.

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