Issuances of Common Stock - Dividend Reinvestment and Stock Purchase Plan (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Dividend Reinvestment and Stock Purchase Plan
Gross proceeds	$ 2,366	$ 2,164
Dividend Reinvestment and Stock Purchase Plan
Dividend Reinvestment and Stock Purchase Plan
Common shares authorized for future issuance (in shares)	26,000,000
Common shares remaining for future issuance (in shares)	11,618,668
Common stock | Dividend Reinvestment and Stock Purchase Plan
Dividend Reinvestment and Stock Purchase Plan
Shares of common stock issued (in shares)	34,000	31,898
Gross proceeds	$ 2,400	$ 2,200