XML 60 R49.htm IDEA: XBRL DOCUMENT v3.19.1
Subsequent events - Additional Information (Detail) - Subsequent Event
Mar. 08, 2019
$ / shares
Feb. 01, 2019
USD ($)
ft²
Subsequent Event [Line Items]    
Dividends Payable, Amount Per Share | $ / shares $ 0.02  
Dividends payable, record date Mar. 31, 2019  
NY [Member]    
Subsequent Event [Line Items]    
Area of Land | ft²   5,000
Operating Leases, Rent Expense | $   $ 9,375