Borrowings - Additional Information (Details)	1 Months Ended				3 Months Ended	12 Months Ended
	Jul. 17, 2015	Nov. 27, 2007 USD ($)	Sep. 15, 2007 USD ($)	Jun. 29, 2007 USD ($)	Dec. 31, 2014	Dec. 31, 2015 USD ($)	Dec. 16, 2005 USD ($)	Mar. 31, 2005 USD ($)
Debt Instrument [Line Items]
Securities Sold Under Agreements To Repurchase Period Description						overnight to seven days
Secured lines of credit						$ 1,400,000,000
Junior subordinated debentures private sales				$ 12,000,000
Trust Preferred Securities Redemption Description						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.
Junior subordinated deferrable interest notes issued						$ 12,400,000
Number of Debt Instruments Acquired						3
Debt Instrument Maturity Period One [Member]
Debt Instrument [Line Items]
Debt maturity date						Dec. 26, 2032
Long-term Debt, Gross						$ 5,200,000
Debt Instrument, Basis Spread on Variable Rate						3.85%
Debt Instrument, Description of Variable Rate Basis						3-month LIBOR rate plus 325 basis points
Debt Instrument Maturity Period Two [Member]
Debt Instrument [Line Items]
Debt maturity date						Mar. 17, 2034
Long-term Debt, Gross						$ 4,100,000
Debt Instrument, Basis Spread on Variable Rate						3.32%
Debt Instrument, Description of Variable Rate Basis						3-month LIBOR rate plus 279 basis points
Debt Instrument Maturity Period Three [Member]
Debt Instrument [Line Items]
Debt maturity date						Feb. 23, 2036
Long-term Debt, Gross						$ 5,200,000
Debt Instrument, Interest Rate During Period						6.37%
Debt Instrument, Interest Rate, Effective Percentage						1.77%
Debt Instrument, Fair Value Disclosure						$ 3,500,000
Debt Instrument, Description of Variable Rate Basis						three month LIBOR rate plus 139 basis points
Debt Instrument Maturity Period Four [Member]
Debt Instrument [Line Items]
Debt maturity date						Dec. 30, 2034
Long-term Debt, Gross						$ 7,200,000
Debt Instrument, Basis Spread on Variable Rate						2.58%
Debt Instrument, Fair Value Disclosure						$ 2,100,000
Debt Instrument, Description of Variable Rate Basis						2-month LIBOR rate plus 198 basis points
Trust I [Member]
Debt Instrument [Line Items]
Junior subordinated debentures private sales						$ 20,000,000
Issued of common equity securities						$ 619,000
Debt Instrument, Description of Variable Rate Basis						3-month LIBOR rate plus 175 basis points
Trust II [Member]
Debt Instrument [Line Items]
Junior subordinated debentures private sales						$ 20,000,000
Issued of common equity securities						$ 619,000
Debt Instrument, Description of Variable Rate Basis						3-month LIBOR rate plus 133 basis points
Trust III [Member]
Debt Instrument [Line Items]
Issued of common equity securities						$ 372,000
Debt Instrument, Description of Variable Rate Basis						the 3-month LIBOR rate plus 135 basis points
Trust I & II [Member]
Debt Instrument [Line Items]
Junior subordinated debentures								$ 20,600,000
Aggregate subordinated debentures							$ 41,200,000
Junior subordinated deferrable interest notes issued						$ 41,200,000
Federal Home Loan Bank [Member]
Debt Instrument [Line Items]
Advances received		$ 25,000,000	$ 25,000,000
Debt maturity date		Sep. 15, 2017	Nov. 27, 2017
Libor Rate [Member] | Trust I [Member]
Debt Instrument [Line Items]
Adjust basis points on variable rate, percentage						2.36%
Libor Rate [Member] | Trust II [Member]
Debt Instrument [Line Items]
Adjust basis points on variable rate, percentage						1.84%
Libor Rate [Member] | Trust III [Member]
Debt Instrument [Line Items]
Adjust basis points on variable rate, percentage						1.86%
Floating Rate Junior Subordinated Deferrable Interest Debentures [Member]
Debt Instrument [Line Items]
Number of Debt Instruments Acquired					3
Floating Rate Junior Subordinated Deferrable Interest Debentures [Member] | Debt Instrument Maturity Period Four [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis	2-month LIBOR rate plus 198 basis points
September 15, 2017 [Member]
Debt Instrument [Line Items]
Fixed rates advances						3.64%
November 27, 2017 [Member]
Debt Instrument [Line Items]
Fixed rates advances						2.70%