Summary of Accumulated Other Comprehensive Income Balances (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Beginning Balance	$ 1,326
Current Period Change	(75)	1,034
Ending Balance	1,251
Net Unrealized Income( Loss) on Non OTTI Securities Available For Sale
Beginning Balance	139
Current Period Change	(88)
Ending Balance	51
Net Unrealized Income (Loss) on OTTI Securities Available For Sale
Beginning Balance	1,237
Current Period Change	(4)
Ending Balance	1,233
Accumulated Net Unrealized Investment Gain (Loss)
Beginning Balance	(50)
Current Period Change	17
Ending Balance	$ (33)