Subsequent Events (Details) (Subsequent event, USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Apr. 30, 2015
Common stock
Subsequent events
Common stock, dividends declared (in dollars per share)	$ 0.1895
Shares issued	5,500,000
Underwriting discounts and offering costs	$ 1.5
Proceeds from common stock offerings, net	$ 276.3
Class F Cumulative Redeemable Preferred Stock
Subsequent events
Preferred stock, dividends declared (in dollars per share)	$ 0.138021