Common Stock Common Stock (Equity Issuances) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock	$ 64,573	$ 1,207	$ 56,380
Common Stock, Shares Authorized	200,000,000	200,000,000
Sales Agency Agreement [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	4,600,000
Common Stock Shares Authorized Under Sales Agency Agreements Remaining Shares Authorized To Sell	3,200,000
Common Stock [Member]
Class of Stock [Line Items]
Shares issued through sales agency agreements	1,409,588	0	1,070,000
Issuance of common stock through sales agency agreements, net of issuance costs	$ 63,571	$ 0	$ 54,721