Common Stock - Narrative (Details) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Class of Stock [Line Items]        
Common stock, outstanding (in shares)   68,358,074 66,318,849  
Common stock sold excluding overallotment shares (in shares) 3,700,000      
Common stock offered and sold (in shares) 4,300,000      
Proceeds from issuance of common stock $ 79,200 $ 0 $ 79,165 $ 0
Overallotment Option        
Class of Stock [Line Items]        
Overallotment option included in sale of stock (percent) 15.00%