Fair Values of Financial Instruments (Details Textual)	9 Months Ended
	Sep. 30, 2012
Maximum [Member]
Fair Values of Financial Instruments (Textual) [Abstract]
Maturity period of certificates of deposit	1 year
Probability of the issue being called prior to final maturity	87.60%
Estimates of the probability of defaults	14.10%
Estimates of the probability of recovery	60.00%
Estimated illiquidity discount	4.50%
Minimum [Member]
Fair Values of Financial Instruments (Textual) [Abstract]
Maturity period of certificates of deposit	90 days
Probability of the issue being called prior to final maturity	84.00%
Estimates of the probability of defaults	11.90%
Estimates of the probability of recovery	40.00%
Estimated illiquidity discount	3.50%