Consolidated Statements of Cash Flows (Parenthetical)	3 Months Ended	6 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Series C Preferred Stock [Member] \| At-The-Market Offerings [Member]
Preferred stock, dividend rate	6.125%	6.125%	6.125%	6.125%

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