XML 20 R7.htm IDEA: XBRL DOCUMENT
v3.10.0.1

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - $ / shares | 6 Months Ended
--- | ---
Jun. 30, 2018 | Jun. 30, 2017
Series A Preferred Stock |  |
Preferred stock dividend rate (in dollars per share) |  | $ 1.74
Series B Preferred Stock |  |
Preferred stock dividend rate (in dollars per share) | $ 1.81 | $ 1.39

X
- Definition The amount per share used to calculated dividend payments on preferred stock. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendRatePerDollarAmount
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesBPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |