Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical)	3 Months Ended
Mar. 31, 2015
Percentage of dividend on convertible preferred stock	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