Borrowings - Additional Information (Detail) (USD $)	0 Months Ended		12 Months Ended				12 Months Ended				0 Months Ended		12 Months Ended
	Nov. 27, 2007	Sep. 25, 2007	Dec. 31, 2013 Quarters	Jun. 29, 2007	Dec. 16, 2005	Mar. 31, 2005	Dec. 31, 2013 Trust I [Member]	Dec. 31, 2013 Trust II [Member]	Dec. 31, 2013 Trust III [Member]	Dec. 31, 2013 Trust I & II [Member]	Nov. 27, 2007 Federal Home Loan Bank [Member]	Sep. 25, 2007 Federal Home Loan Bank [Member]	Dec. 31, 2013 Federal Home Loan Bank [Member]	Dec. 31, 2013 Federal Reserve Bank Advances [Member]	Dec. 31, 2012 Federal Reserve Bank Advances [Member]	Dec. 31, 2013 Libor Rate [Member] Trust I [Member]	Dec. 31, 2013 Libor Rate [Member] Trust II [Member]	Dec. 31, 2013 Libor Rate [Member] Trust III [Member]	Dec. 31, 2013 September 15, 2017 [Member]	Dec. 31, 2013 November 27, 2017 [Member]
Debt Instrument [Line Items]
Securities sold under agreements to repurchase with maturities period			Overnight to seven days
Advances received											$ 25,000,000	$ 25,000,000
Debt maturity date	Nov. 27, 2017	Sep. 15, 2017
Fixed rates advances																			3.64%	2.70%
Period of perpetual option conversion													3 months
Secured lines of credit			894,106,000
Junior subordinated debentures					20,619,000	20,619,000
Aggregate subordinated debentures					41,238,000
Junior subordinated debentures private sales							20,000,000	20,000,000	12,000,000
Additional Junior subordinated debentures				12,372,000
Basis points on variable rate, percentage							1.75%	1.33%	1.35%
Adjust basis points on variable rate, percentage																2.00%	1.57%	1.59%
Trust Preferred securities redemption details			The trust preferred securities have original maturities of thirty years, and may be redeemed without penalty on or after June 10, 2010, March 15, 2011, and September 15, 2012, respectively, upon approval of the Federal Reserve or upon occurrence of certain events affecting their tax or regulatory capital treatment.
Issued of common equity securities							619,000	619,000	372,000
Original debt maturity, period			30 years
Junior subordinated deferrable interest notes issued									12,400,000	41,200,000
Quarterly interest payment period for notes			20
Trust preferred securities issued														$ 52,000,000	$ 52,000,000