Schedule of Options Granted, Classified into Range of Exercise Price (Detail) - $ / shares		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Number of options		1,455,908	[1]	2,406,455
Outstanding, Weighted average remaining contractual life (years)		4 years 8 months 12 days
Outstanding, Weighted average exercise price		$ 19.76
Exercisable, Number of options	[2]	972,229
Exercisable, Weighted average remaining contractual life (years)		3 years 10 months 24 days
Exercisable, Weighted average exercise price	[2]	$ 19.88
12.60 - 15.54
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, Lower limit		12.60
Range of exercise price, Upper limit		$ 15.54
Outstanding, Number of options		396,969
Outstanding, Weighted average remaining contractual life (years)		4 years 8 months 12 days
Outstanding, Weighted average exercise price		$ 14.63
Exercisable, Number of options		237,614
Exercisable, Weighted average remaining contractual life (years)		4 years 1 month 6 days
Exercisable, Weighted average exercise price		$ 14.59
16.08 - 18.62
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, Lower limit		16.08
Range of exercise price, Upper limit		$ 18.62
Outstanding, Number of options		381,257
Outstanding, Weighted average remaining contractual life (years)		4 years 1 month 6 days
Outstanding, Weighted average exercise price		$ 16.72
Exercisable, Number of options		292,617
Exercisable, Weighted average remaining contractual life (years)		4 years 1 month 6 days
Exercisable, Weighted average exercise price		$ 16.73
19.36 - 24.86
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, Lower limit		19.36
Range of exercise price, Upper limit		$ 24.86
Outstanding, Number of options		438,579
Outstanding, Weighted average remaining contractual life (years)		4 years 4 months 24 days
Outstanding, Weighted average exercise price		$ 21.65
Exercisable, Number of options		306,895
Exercisable, Weighted average remaining contractual life (years)		3 years 4 months 24 days
Exercisable, Weighted average exercise price		$ 22.26
27.01 - 32.34
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise price, Lower limit		27.01
Range of exercise price, Upper limit		$ 32.34
Outstanding, Number of options		239,103
Outstanding, Weighted average remaining contractual life (years)		6 years 4 months 24 days
Outstanding, Weighted average exercise price		$ 29.67
Exercisable, Number of options		135,103
Exercisable, Weighted average remaining contractual life (years)		3 years 10 months 24 days
Exercisable, Weighted average exercise price		$ 30.62

[1] Due to the ceiling imposed on the SAR grants, the outstanding amount equals a maximum of 1,305,719 shares of the Company's common stock issuable upon exercise.

[2] Due to the ceiling imposed on the SAR grants, the exercisable amount equals a maximum of 882,273 shares of the Company's common stock issuable upon exercise.