Benefit Plans - Options Outstanding and Options Exercisable by Exercise Price with Weighted-Average Remaining Contractual Life for Options Outstanding and Weighted-Average Exercise Price (Detail) (USD $)	12 Months Ended
Dec. 31, 2013
Exercise Price 15 - 20 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 15
Exercise Price Upper Range Limit	$ 20
Options Outstanding, Number	237,742
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 1 month 24 days
Options Outstanding, Weighted-Average Grant Date Value	$ 15.62
Options Exercisable, Number	206,742
Options Exercisable, Weighted-Average Grant Date Value	$ 15.62
Exercise Price 20 - 25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 20
Exercise Price Upper Range Limit	$ 25
Options Outstanding, Number	679,825
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	1 year 8 months 27 days
Options Outstanding, Weighted-Average Grant Date Value	$ 22.09
Options Exercisable, Number	616,520
Options Exercisable, Weighted-Average Grant Date Value	$ 21.94
Exercise Price 25 - 30 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 25
Exercise Price Upper Range Limit	$ 30
Options Outstanding, Number	741,195
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	3 years 5 months 12 days
Options Outstanding, Weighted-Average Grant Date Value	$ 29.09
Options Exercisable, Number	496,825
Options Exercisable, Weighted-Average Grant Date Value	$ 29.23
Exercise Price 30 - 35 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 30
Exercise Price Upper Range Limit	$ 35
Options Outstanding, Number	108,300
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	5 years 5 months 23 days
Options Outstanding, Weighted-Average Grant Date Value	$ 31.73
Options Exercisable, Number	8,150
Options Exercisable, Weighted-Average Grant Date Value	$ 31.55
Exercise Price 35 - 40 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 35
Exercise Price Upper Range Limit	$ 40
Options Outstanding, Number	5,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	6 years 11 months 1 day
Options Outstanding, Weighted-Average Grant Date Value	$ 38.89
Options Exercisable, Number
Options Exercisable, Weighted-Average Grant Date Value
Exercise Price 15 - 40 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range Limit	$ 15
Exercise Price Upper Range Limit	$ 40
Options Outstanding, Number	1,772,062
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	2 years 8 months 27 days
Options Outstanding, Weighted-Average Grant Date Value	$ 24.68
Options Exercisable, Number	1,328,237
Options Exercisable, Weighted-Average Grant Date Value	$ 23.73

Benefit Plans - Options Outstanding and Options Exercisable by Exercise Price with Weighted-Average Remaining Contractual Life for Options Outstanding and Weighted-Average Exercise Price (Detail) (USD $)

12 Months Ended

Dec. 31, 2013

Exercise Price 15 - 20 [Member]

Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]

Exercise Price Lower Range Limit

$ 15

Exercise Price Upper Range Limit

$ 20

Options Outstanding, Number

237,742

Options Outstanding, Weighted-Average Remaining Contractual Life (Years)

2 years 1 month 24 days