Software Licenses - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 License	Mar. 31, 2012
Business Combinations [Abstract]
Number of third-party software licenses	35,000,000
Software licenses, period	4 years
Amount distributed for licenses	$ 6.4
Amortized cost of revenue, period	3 years 6 months
Additional cost for amortized cost of revenue	10.2
Extent of billed license revenue	460
Extent of billed license revenue, period	4 years
Amortization expense related to agreements	$ 0.7	$ 0.4