Effective Income Tax Rate Reconciliation (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Statutory federal rate	35.00%	35.00%	35.00%
State income tax, net of federal benefit	2.80%	3.40%	3.20%
Illinois state EDGE credit net of valuation allowance	(0.40%)	(0.20%)	(1.00%)
Impact of sale of global data business		0.70%	(15.50%)
Americas Data assets allocation			(4.70%)
Other	(0.20%)	0.20%	0.40%
Effective income tax rate	37.20%	39.10%	17.40%