Quarterly report pursuant to Section 13 or 15(d)

Earnings Per Share and Earnings Per Unit - Additional Information (Detail)

v3.10.0.1
Earnings Per Share and Earnings Per Unit - Additional Information (Detail) - shares
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Restricted Stock [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Securities not included in the effect of dilutive securities 88,621 133,179 105,935 139,107
Stock Options [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Securities not included in the effect of dilutive securities   17,500 7,333 14,667