Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Performance Share Units - Additional Information (Detail)

v3.19.1
Stock Based Compensation - Performance Share Units - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Performance Share Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Allocated share-based compensation expense $ 0 $ 202,702