Quarterly report pursuant to Section 13 or 15(d)

Stock Compensation - Summary of Nonvested Shares Related to the 2007 and 2017 Plan (Detail)

v3.10.0.1
Stock Compensation - Summary of Nonvested Shares Related to the 2007 and 2017 Plan (Detail)
9 Months Ended
Sep. 30, 2018
$ / shares
shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Nonvested, Shares, Beginning of Period | shares 2,303,557
Granted, Shares | shares 1,798,500
Vested, Shares | shares (820,283)
Cancelled, Shares | shares (121,333)
Nonvested, Shares, End of Period | shares 3,160,441
Nonvested, Weighted Average Grant-Date Fair Value, Beginning of Period | $ / shares $ 26.25
Granted, Weighted Average Grant-Date Fair Value | $ / shares 38.14
Vested, Weighted Average Grant-Date Fair Value | $ / shares 22.63
Cancelled, Weighted Average Grant-Date Fair Value | $ / shares 29.56
Nonvested, Weighted Average Grant-Date Fair Value, End of Period | $ / shares $ 33.82