Issuances of Common Stock - Dividend Reinvestment and Stock Purchase Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Dividend Reinvestment and Stock Purchase Plan
Gross proceeds			$ 6,922	$ 6,259
DRSPP
Dividend Reinvestment and Stock Purchase Plan
Dividend Reinvestment and Stock Purchase Plan, authorized shares (in shares)	26,000,000		26,000,000
Shares remaining for future issuance (in shares)	11,539,247		11,539,247
Common stock | DRSPP
Dividend Reinvestment and Stock Purchase Plan
Shares of common stock issued (in shares)	34,604	29,801	113,421	89,219
Gross proceeds	$ 2,100	$ 2,100	$ 6,900	$ 6,300