Commitments and Contingencies (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2011
Derivative Liability, Notional Amount	$ 63,000,000	$ 48,000,000	$ 46,500,000
Derivative, Gain (Loss) on Derivative, Net	$ 280,000	$ 354,000	$ 195,000