Quantitative Information About Significant Unobservable Inputs (Parenthetical) (Detail) (Other assets, Equity Warrant Asset)	12 Months Ended
	Dec. 31, 2012 Year	Dec. 31, 2011
Other assets | Equity Warrant Asset
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount for Lack of Marketability	22.50%	15.00%
Weighted average contractual remaining term	6.4
Estimated remaining life	2.9
Financial Instruments Fair Value Assumptions Weighted Average Remaining Life	45.00%	40.00%