Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	Feb. 12, 2018	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Feb. 29, 2012
Stockholders Equity
Proceeds from issuance of common stock			$ 23,367
Repurchases unsettled (in shares)				0
Common Stock
Stockholders Equity
Issuance of shares (in shares)		3,373,000
Authorized amount to repurchase					$ 50,000
Stock repurchase remaining authorized amount				$ 14,300
Public offering
Stockholders Equity
Proceeds from issuance of common stock	$ 23,400
Underwriting discounts and commissions and offering expenses	$ 1,900
Public offering | Common Stock
Stockholders Equity
Issuance of shares (in shares)	3,373,332
Price per share (in dollars per share)	$ 7.50