XML 72 R61.htm IDEA: XBRL DOCUMENT v3.10.0.1
Income Per Share Information - Additional Information (Detail) - shares
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Contingently Issuable Shares [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Shares excluded in computation of diluted income per share 75,851 1,317,651 51,946 2,037,886