Fair Value of Financial Instruments - Quantitative Information About Significant Unobservable Inputs (Parenthetical) (Detail) (Other assets, Equity warrant assets)	Mar. 31, 2013
Other assets | Equity warrant assets
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Weighted average contractual remaining term	6 years 4 months 28 days
Estimated remaining life	2 years 10 months 21 days