7. Fair Value Instruments (Detail) - (Table 3) Investment roll-forward using Level 3 unobservable inputs (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member]
Balance at				$ 1,281,000
Other than temporary impairment loss	27,666	86,707	(28,000)
Balance at			$ 1,253,000	$ 1,281,000