Quarterly report pursuant to Section 13 or 15(d)

Earnings per Share - Additional Information (Detail)

v3.8.0.1
Earnings per Share - Additional Information (Detail) - shares
3 Months Ended 6 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2018
Mar. 31, 2017
Earnings Per Share [Abstract]        
Common stock excluded from calculation of diluted earnings per share 63,000 768,985 63,000 958,035