CONSOLIDATED STATEMENTS OF CASH FLOWS [Parenthetical]	6 Months Ended
Jun. 30, 2018
Series D Preferred Stock [Member]
Preferred Stock, Dividend Rate, Percentage	7.125%
Series B Preferred Stock [Member]
Preferred Stock, Dividend Rate, Percentage	6.00%

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