Federal Home Loan Bank Borrowings - Federal Home Loan Bank Borrowings by Year of Maturity and Applicable Interest Rate (Detail) (USD $) In Thousands, unless otherwise specified							12 Months Ended				12 Months Ended			12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended		12 Months Ended
	Dec. 31, 2012	Aug. 06, 2012	Dec. 31, 2011	Dec. 31, 2012 Cash Management Advance [Member]	Dec. 31, 2011 Cash Management Advance [Member]	Dec. 31, 2011 2012 [Member]	Dec. 31, 2012 2012 [Member] Minimum [Member]	Dec. 31, 2012 2012 [Member] Maximum [Member]	Dec. 31, 2012 2013 [Member]	Dec. 31, 2011 2013 [Member]	Dec. 31, 2012 2013 [Member] Minimum [Member]	Dec. 31, 2012 2013 [Member] Maximum [Member]	Dec. 31, 2011 2014 [Member]	Dec. 31, 2012 2014 [Member] Minimum [Member]	Dec. 31, 2012 2014 [Member] Maximum [Member]	Dec. 31, 2012 2015 [Member]	Dec. 31, 2011 2015 [Member]	Dec. 31, 2012 2015 [Member] Minimum [Member]	Dec. 31, 2012 2015 [Member] Maximum [Member]	Dec. 31, 2012 2016 [Member]	Dec. 31, 2011 2016 [Member]	Dec. 31, 2012 2016 [Member] Minimum [Member]	Dec. 31, 2012 2016 [Member] Maximum [Member]	Dec. 31, 2012 2017 [Member]	Dec. 31, 2011 2017 [Member]	Dec. 31, 2012 2017 [Member] Maximum [Member]	Dec. 31, 2012 Thereafter [Member]	Dec. 31, 2012 Thereafter [Member] Maximum [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Current Rates											0.27	3.84						0.60	1.6			1.84	2.36			2.28		3.85
FHLB borrowings maturity date						2012				2013			2014				2015				2016				2017
Federal Home Loan Bank borrowings	$ 118,000	$ 39,000	$ 101,500			$ 60,500			$ 77,000	$ 22,000			$ 13,500			$ 13,500	$ 3,500			$ 22,500	$ 2,000			$ 3,000			$ 2,000