Capital Stock - Summary of Option Activity under Plans and Related Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Stock Options Outstanding, Outstanding - Beginning balance	1,675,506	1,989,237	2,871,005
Number of Stock Options Outstanding, Granted	1,256,559	631,775	698,240
Number of Shares, Options assumed in acquisitions	72,607
Number of Stock Options Outstanding, Exercised	(496,297)	(687,719)	(1,272,941)
Number of Stock Options Outstanding, Cancelled or forfeited	(264,012)	(257,787)	(307,067)
Number of Stock Options Outstanding, Outstanding - Ending balance	2,244,363	1,675,506	1,989,237	2,871,005
Weighted Average Exercise Price of Stock Options Outstanding, Beginning balance	$ 23.78	$ 14.08	$ 4.15
Vested and expected to vest, Number of Shares	2,006,285
Weighted Average Exercise Price, Granted	$ 41.39	$ 36.55	$ 31.80
Number of Shares, Exercisable	590,308
Weighted Average Exercise Price, Options assumed in acquisitions	$ 13.30
Weighted Average Exercise Price, Exercised	$ 14.85	$ 6.94	$ 2.41
Weighted Average Exercise Price, Cancelled or forfeited	$ 35.85	$ 25.11	$ 9.98
Weighted Average Exercise Price of Stock Options Outstanding, Ending balance	$ 33.83	$ 23.78	$ 14.08	$ 4.15
Aggregate Intrinsic Value - Beginning balance	$ 40,813	$ 35,513	$ 88,012
Vested and expected to vest, Weighted-Average Exercise Price	$ 33.07
Aggregate Intrinsic Value - Ending balance	38,457	40,813	35,513	88,012
Weighted Average Exercise Price, Exercisable	$ 21.66
Vested and expected to vest, Aggregate Intrinsic Value	35,688
Weighted- Average Remaining Contractual Term (in years)	8 years 3 months 7 days	8 years 4 days	8 years 1 month 2 days	7 years 10 months 10 days
Aggregate Intrinsic Value, Exercisable	$ 16,425
Vested and expected to vest, Weighted-Average Remaining Contractual Term (in years)	8 years 2 months 12 days
Weighted Average Remaining Contractual Term (in years), Exercisable	6 years 6 months 22 days