Quarterly report pursuant to Section 13 or 15(d)

Stock Compensation - Summary of Nonvested Shares Related to Equity Incentive Plans (Detail)

v3.8.0.1
Stock Compensation - Summary of Nonvested Shares Related to Equity Incentive Plans (Detail)
9 Months Ended
Sep. 30, 2017
$ / shares
shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Nonvested, Shares, Beginning of Period | shares 3,043,164
Granted, Shares | shares 415,100
Vested, Shares | shares (769,874)
Cancelled, Shares | shares (78,000)
Nonvested, Shares, End of Period | shares 2,610,390
Nonvested, Weighted Average Grant-Date Fair Value, Beginning of Period | $ / shares $ 24.57
Granted, Weighted Average Grant-Date Fair Value | $ / shares 23.14
Vested, Weighted Average Grant-Date Fair Value | $ / shares 21.92
Cancelled, Weighted Average Grant-Date Fair Value | $ / shares 32.62
Nonvested, Weighted Average Grant-Date Fair Value, End of Period | $ / shares $ 24.88