Shareholders' Equity Shareholders' Equity (Details) - USD ($) $ in Thousands, shares in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock	$ 217,513	$ 4,592
At-the-market equity issuance [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	8.3
Proceeds from Issuance of Common Stock	$ 213,600
Gross Proceeds [Member] | At-the-market equity issuance [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock	$ 216,200