Equity Offering (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Jun. 30, 2015
Class of Stock [Line Items]
Proceeds from issuance of common stock net of offering expenses	$ 381.1	$ 398.6
Common Stock
Class of Stock [Line Items]
Shares issued through public equity offering (in shares)	18,170,000	5,700,000