Nature of Business and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Payments for partnership dissolved				$ 1,391
Percentage of receivables as of December 31, 2015, 2014		No customer accounted for more than 10% of the Company's consolidated receivables balance as of December 31, 2016 or 2015.
Amount of off balance sheet settlement funds		$ 270,000	$ 260,200
Goodwill measurement period		1 year
Increase to net cash provided by operating activities		$ 99,830	187,994	160,833
Increase to net cash used in financing activities		(251,076)	44,640	66,275
Cumulative-effect adjustment to retained earnings, net of tax		$ (99)
Adjustments for New Accounting Pronouncement [Member]
Summary Of Significant Accounting Policies [Line Items]
Increase to net cash provided by operating activities			4,900	11,800
Increase to net cash used in financing activities			$ 4,900	11,800
Cumulative-effect adjustment to retained earnings, net of tax	$ 700
Cumulative-effect adjustment to retained earnings, tax	$ 400
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		20 years
Software Acquired or Developed for Internal Use | Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		3 years
Software Acquired or Developed for Internal Use | Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		10 years
Cornastone Technology Investments (Proprietary) Limited
Summary Of Significant Accounting Policies [Line Items]
Payments for partnership dissolved				$ 1,500