XML 87 R77.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stockholders' Equity - Additional Information (Details) - USD ($)
9 Months Ended
Apr. 12, 2018
Sep. 30, 2018
Sep. 30, 2017
Class Of Stock [Line Items]      
Stock issued during period shares 5,405,000    
Shares issued price per share $ 37.50    
Gross proceeds from issuance of common stock $ 202,688,000    
Net proceeds after underwriting discounts and offering expenses $ 192,053,000 $ 192,053,000 $ 65,528,000
Over-Allotment Option      
Class Of Stock [Line Items]      
Stock issued during period shares 705,000