CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Series A Preferred Stock
Preferred stock dividend rate (in dollars per share)		$ 0.87
Series B Preferred Stock
Preferred stock dividend rate (in dollars per share)	$ 0.83	$ 0.67

The amount per share used to calculated dividend payments on preferred stock.

No definition available.

Name:	us-gaap_PreferredStockDividendRatePerDollarAmount
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration