Quarterly report pursuant to Section 13 or 15(d)

Summary of Restricted Stock Activity (Detail)

v3.8.0.1
Summary of Restricted Stock Activity (Detail) - Restricted Stock
3 Months Ended
Mar. 31, 2018
$ / shares
shares
Shares of Restricted Stock  
Shares of Restricted Stock, Beginning balance | shares 650,581
Shares of Restricted Stock, Granted | shares 260,019
Shares of Restricted Stock, Vested | shares (202,341)
Shares of Restricted Stock, Forfeited | shares (11,303)
Shares of Restricted Stock, Ending balance | shares 696,956
Shares of Restricted Stock, Unvested restricted stock | shares 696,956
Weighted Average Grant Date Fair Value  
Weighted Average Grant Date Fair Value Outstanding, Beginning | $ / shares $ 35.81
Weighted Average Grant Date Fair Value, Granted | $ / shares 39.03
Weighted Average Grant Date Fair Value, Vested | $ / shares 29.45
Weighted Average Grant Date Fair Value, Forfeited | $ / shares 37.96
Weighted Average Grant Date Fair Value Outstanding, Ending | $ / shares 38.82
Weighted Average Grant Date Fair Value, Unvested restricted stock | $ / shares $ 38.82