Benefit Plans - Summary of Characteristics of Options Outstanding (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding at 12/31/14	2,961
Weighted-Average Remaining Contractual Life (Years)	5 years 8 months 12 days
Weighted-Average Exercise Price	$ 22.48
Exercisable at 12/31/14	1,922
Weighted-Average Exercise Price	$ 25.75
0.00 - 6.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Limit	$ 0.00
Exercise Price Range, Upper Limit	$ 6.50
Outstanding at 12/31/14	471
Weighted-Average Remaining Contractual Life (Years)	4 years
Weighted-Average Exercise Price	$ 6.01
Exercisable at 12/31/14	471
Weighted-Average Exercise Price	$ 6.01
6.51 - 12.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Limit	$ 6.51
Exercise Price Range, Upper Limit	$ 12.50
Outstanding at 12/31/14	200
Weighted-Average Remaining Contractual Life (Years)	5 years 3 months 18 days
Weighted-Average Exercise Price	$ 10.42
Exercisable at 12/31/14	197
Weighted-Average Exercise Price	$ 10.39
12.51 - 21.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Limit	$ 12.51
Exercise Price Range, Upper Limit	$ 21.00
Outstanding at 12/31/14	1,480
Weighted-Average Remaining Contractual Life (Years)	8 years 2 months 12 days
Weighted-Average Exercise Price	$ 15.88
Exercisable at 12/31/14	444
Weighted-Average Exercise Price	$ 14.56
21.01 - 45.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Limit	$ 21.01
Exercise Price Range, Upper Limit	$ 45.50
Outstanding at 12/31/14	490
Weighted-Average Remaining Contractual Life (Years)	2 years
Weighted-Average Exercise Price	$ 38.74
Exercisable at 12/31/14	490
Weighted-Average Exercise Price	$ 38.74
45.51 - 69.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Limit	$ 45.51
Exercise Price Range, Upper Limit	$ 69.50
Outstanding at 12/31/14	320
Weighted-Average Remaining Contractual Life (Years)	1 year 9 months 18 days
Weighted-Average Exercise Price	$ 59.96
Exercisable at 12/31/14	320
Weighted-Average Exercise Price	$ 59.96