Stock-Based Compensation Plans - Summary of Nonvested Transaction Restricted Share Awards Issued under Stock Incentive Plan and Changes During Period (Detail) - S1 Corporation 2003 Stock Incentive Plan [Member]	9 Months Ended
	Sep. 30, 2015 $ / shares shares
Nonvested Restricted Share Awards
Beginning Balance | shares	17,565
Forfeited | shares	(4,364)
Ending Balance | shares	13,201
Weighted-Average Grant Date Fair Value
Beginning Balance	$ 11.80
Forfeited	11.80
Ending Balance	$ 11.80