Equity Other Equity Activity (Details) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) shares $ / shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2016 $ / shares
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		$ 4,220,766	$ 323,798
At the Market Stock Offering Program, capacity remaining	$ 150,000	$ 150,000
Preferred Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01		$ 0.01
Common Stock, Capital Shares Reserved for Future Issuance	$ 500,000	$ 500,000
At the Market Program [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		22,009
Payments of Stock Issuance Costs		200
Common Stock [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock	$ 402	$ 454
Stock Issued During Period, Shares, New Issues | shares	40,150,000	45,255,158	0
Common Stock [Member] | July 2017 Equity Offering [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock	$ 3,800,000
Sale of Stock, Transaction Date	Jul. 26, 2017
Stock Issued During Period, Shares, New Issues | shares	40,150,000
Common Stock [Member] | At the Market Program [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock			$ 38
Stock Issued During Period, Shares, New Issues | shares		242,300	3,828,064
Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	6.875%
Preferred Stock, Per Share Sales Price | $ / shares	$ 1,000
Preferred Stock, Automatic Conversion Date		Aug. 01, 2020
Preferred Stock [Member] | July 2017 Equity Offering [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	6.875%
Preferred Stock, Par or Stated Value Per Share | $ / shares	$ 0.01	$ 0.01
Preferred Stock, Per Share Sales Price | $ / shares	$ 1,000
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 1,600,000
Sale of Stock, Transaction Date	Jul. 26, 2017
Stock Issued During Period, Shares, New Issues | shares	1,650,000
Minimum [Member]
Class of Stock [Line Items]
Conversion factor, Preferred Stock | shares		8.6806
Maximum [Member]
Class of Stock [Line Items]
Conversion factor, Preferred Stock | shares		10.4167