Share Based Compensation - Schedule of Stock Options Exercise Price (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Class of Stock [Line Items]
Exercise Price, Options Outstanding	5,131
Exercise Price, Options Exercisable	2,370
Exercise Price Range 1 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 5.20
Exercise Price, Maximum	$ 6.548
Exercise Price, Options Outstanding	9
Exercise Price, Options Exercisable	9
Exercise Price Range 2 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 10.00
Exercise Price, Maximum	$ 14.000
Exercise Price, Options Outstanding	803
Exercise Price, Options Exercisable	803
Exercise Price Range 3 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 18.00
Exercise Price, Maximum	$ 23.000
Exercise Price, Options Outstanding	1,515
Exercise Price, Weighted Average Remaining Vesting Life in Years	6 months 22 days
Exercise Price, Options Exercisable	996
Exercise Price Range 4 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 27.83
Exercise Price, Maximum	$ 34.720
Exercise Price, Options Outstanding	190
Exercise Price, Weighted Average Remaining Vesting Life in Years	9 months 29 days
Exercise Price, Options Exercisable	86
Exercise Price Range 5 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 35.04
Exercise Price, Maximum	$ 40.650
Exercise Price, Options Outstanding	974
Exercise Price, Weighted Average Remaining Vesting Life in Years	1 year 5 months 27 days
Exercise Price, Options Exercisable	447
Exercise Price Range 6 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 47.63
Exercise Price, Maximum	$ 58.020
Exercise Price, Options Outstanding	24
Exercise Price, Weighted Average Remaining Vesting Life in Years	1 year 10 months 28 days
Exercise Price Range 7 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 74.99
Exercise Price, Maximum	$ 111
Exercise Price, Options Outstanding	325
Exercise Price, Weighted Average Remaining Vesting Life in Years	2 years 8 months 12 days
Exercise Price, Options Exercisable	29
Excercise Price Range 8 [Member]
Class of Stock [Line Items]
Exercise Price, Minimum	$ 115
Exercise Price, Maximum	$ 150
Exercise Price, Options Outstanding	1,291
Exercise Price, Weighted Average Remaining Vesting Life in Years	3 years 2 months 1 day