Shareholders' Equity - Schedule of Declared Distributions (Details) - $ / shares	Oct. 09, 2015	Jul. 09, 2015	Apr. 08, 2015	Jan. 16, 2015
Series D
Class of Stock [Line Items]
Dividend declared (in dollars per share)		$ 0.40625	$ 0.40625	$ 0.40625
Series D | Subsequent event
Class of Stock [Line Items]
Dividend declared (in dollars per share)	$ 0.40625
Series E
Class of Stock [Line Items]
Dividend declared (in dollars per share)		$ 0.453125	$ 0.453125	$ 0.453125
Series E | Subsequent event
Class of Stock [Line Items]
Dividend declared (in dollars per share)	$ 0.453125