Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Status of Non-Vested Restricted Stock and Restricted Stock Unit Grants Related to Stock Plans (Detail)

v3.8.0.1
Employee Benefit Plans - Status of Non-Vested Restricted Stock and Restricted Stock Unit Grants Related to Stock Plans (Detail)
shares in Thousands
12 Months Ended
Dec. 31, 2017
$ / shares
shares
Compensation And Retirement Disclosure [Abstract]  
Non-vested Restricted Stock Awards and Restricted Stock Units, Beginning Balance | shares 2,180
Non-vested Restricted Stock Awards and Restricted Stock Units, Granted | shares 600
Non-vested Restricted Stock Awards and Restricted Stock Units, Forfeited | shares (131)
Non-vested Restricted Stock Awards and Restricted Stock Units, Vested | shares (450)
Non-vested Restricted Stock Awards and Restricted Stock Units, Ending Balance | shares 2,199
Weighted Average Grant Date Fair Value per Share, Beginning Balance | $ / shares $ 20.86
Weighted Average Grant Date Fair Value per Share, Granted | $ / shares 22.88
Weighted Average Grant Date Fair Value per Share, Forfeited | $ / shares 16.59
Weighted Average Grant Date Fair Value per Share, Vested | $ / shares 20.42
Weighted Average Grant Date Fair Value per Share, Ending Balance | $ / shares $ 21.76