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Share-Based Payment Awards - Summary of Deferred Stock Unit Activity (Detail) - Deferred Stock Units [Member]
9 Months Ended
Sep. 30, 2019
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of Stock Units Outstanding, Beginning Balance | shares 35,418
Number of Stock Units, Vested | shares (35,418)
Weighted Average Grant Date Fair Value Nonvested, Beginning balance | $ / shares $ 1.95
Weighted Average Grant Date Fair value, Vested | $ / shares $ 1.95