Stock-Based Compensation Plans - Summary of Stock Options Issued Pursuant to Stock Incentive Plans (Detail)	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Number of Shares
Outstanding, Beginning Balance | shares	6,791,375
Granted | shares	864,800
Exercised | shares	(529,697)
Forfeited | shares	(103,751)
Expired | shares	(14,783)
Outstanding, Ending Balance | shares	7,007,944
Number of Shares Exercisable, Ending Balance | shares	4,167,453
Weighted-Average Exercise Price
Beginning Balance | $ / shares	$ 15.54
Granted | $ / shares	20.12
Exercised | $ / shares	13.28
Forfeited | $ / shares	18.12
Expired | $ / shares	20.42
Ending Balance | $ / shares	16.23
Weighted-Average Exercise Price Exercisable, Ending Balance | $ / shares	$ 14.45
Weighted-Average Remaining Contractual Term (Years)
Weighted Average Remaining Contractual Term (Years), Outstanding as of end of period	7 years 26 days
Weighted-Average Remaining Contractual Term (Years), Exercisable as of end of period	5 years 9 months 11 days
Aggregate Intrinsic Value of In-the-Money Options
Aggregate Intrinsic Value of In-the-Money Options, Outstanding as of end of period | $	$ 36,159,173
Aggregate Intrinsic Value of In-the-Money Options, Exercisable as of end of period | $	$ 28,920,839