Equity - At-the-Market (ATM) Programs (Details) - Common stock - USD ($) $ in Millions	1 Months Ended	31 Months Ended
	Mar. 31, 2017	Mar. 31, 2018	Oct. 31, 2017	Sep. 30, 2015
At-the-market (ATM) Programs
Share issuances, net of costs (in shares)	11,850,000
ATM
At-the-market (ATM) Programs
Share issuances, net of costs (in shares)		14,407,529
Proceeds from At-the-Market (ATM) program		$ 824.8
ATM | Maximum
At-the-market (ATM) Programs
Shares authorized			17,000,000	12,000,000