Equity Offerings - Narrative (Details) - Distribution Agreement - USD ($) $ / shares in Units, shares in Thousands		9 Months Ended
	Nov. 03, 2017	Sep. 30, 2019	Sep. 30, 2020
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price	$ 125,000,000.0
Gross proceeds from sales of common stock		$ 38,500,000
Issuance costs on sales of common stock		$ 700,000
Number of shares sold (in shares)		460
Price per share sold (in dollars per share)		$ 83.81
Aggregate value of shares available to be offered			$ 31,500,000