Stock-Based Compensation Plans - Summary of Stock Options Issued Pursuant to Stock Incentive Plans (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015
Number of Shares
Outstanding, Beginning Balance	5,282,693
Granted	2,055,514
Exercised	(664,229)
Cancelled	(2,575)
Outstanding, Ending Balance	6,671,403
Number of Shares Exercisable, Ending Balance	3,689,027
Weighted-Average Exercise Price
Beginning Balance	$ 12.06
Granted	$ 19.12
Exercised	$ 10.41
Cancelled	$ 17.15
Ending Balance	$ 14.40
Weighted Average Exercise Price Exercisable, Ending Balance	$ 10.76
Weighted-Average Remaining Contractual Term (Years)
Weighted Average Remaining Contractual Term (Years), Outstanding as of end of period	14 years 4 months 24 days
Weighted Average Remaining Contractual Term (Years), Exercisable as of end of period	10 years 9 months 4 days
Aggregate Intrinsic Value of In-the-Money Options
Aggregate Intrinsic Value of In-the-Money Options, Outstanding as of end of period	$ 48,465,441
Aggregate Intrinsic Value of In-the-Money Options, Exercisable as of end of period	40,228,828
Online Resources Corporation [Member]
Number of Shares
Outstanding, Beginning Balance	46,512
Exercised	(240)
Cancelled	(6,366)
Outstanding, Ending Balance	39,906
Number of Shares Exercisable, Ending Balance	39,906
Weighted-Average Exercise Price
Beginning Balance	$ 36.73
Exercised	$ 13.92
Cancelled	$ 46.80
Ending Balance	$ 35.27
Weighted Average Exercise Price Exercisable, Ending Balance	$ 35.27
Weighted-Average Remaining Contractual Term (Years)
Weighted Average Remaining Contractual Term (Years), Outstanding as of end of period	1 year 7 months 13 days
Weighted Average Remaining Contractual Term (Years), Exercisable as of end of period	1 year 7 months 13 days
Aggregate Intrinsic Value of In-the-Money Options
Aggregate Intrinsic Value of In-the-Money Options, Outstanding as of end of period	51,493
Aggregate Intrinsic Value of In-the-Money Options, Exercisable as of end of period	$ 51,943