Stock Based Compensation - Summary of Changes in Number of Shares of Restricted Stock and Restricted Stock Units (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares, Outstanding, Beginning balance	716	634	472
Shares, Granted	126	467	358
Shares, Cancelled	(52)	(76)	(31)
Shares, Issued	(293)	(309)	(165)
Shares, Outstanding, Ending balance	497	716	634
Weighted Average Grant Date Fair Value, Outstanding, Beginning balance	$ 121.38	$ 67.83	$ 28.98
Weighted Average Grant Date Fair Value, Granted	151.33	146.12	92.16
Weighted Average Grant Date Fair Value, Cancelled	135.92	31.48	35.42
Weighted Average Grant Date Fair Value, Issued	85.40	74.56	30.93
Weighted Average Grant Date Fair Value, Outstanding, Ending balance	$ 149.40	$ 121.38	$ 67.83