Borrowings - Additional Information (Details) - USD ($)		1 Months Ended				12 Months Ended
	Apr. 07, 2016	Nov. 27, 2017	Jul. 17, 2015	Sep. 15, 2007	Jun. 29, 2007	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 16, 2005	Mar. 31, 2005
Debt Instrument [Line Items]
Securities Sold Under Agreements To Repurchase Period Description						overnight to seven days
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, 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	$ 12,400,000
Number of Debt Instruments Acquired						3
Early redemption cost for Federal Home Loan Bank advances						$ 1,777,000	$ 0	$ 0
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
Secured Lines of Credit [Member]
Debt Instrument [Line Items]
Secured lines of credit						1,000,000,000
Early redemption cost for Federal Home Loan Bank advances	$ 1,800,000
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Repayment and Penalties	$ 50,000,000
Advances from Federal Home Loan Banks						$ 415,000
Federal Home Loan Bank, Advances, Activity for Year, Average Interest Rate at Period End						0.62%
Federal Home Loan Bank, Advances, Activity for Year, Average Interest Rate for Year						0.63%
Federal Home Loan Bank [Member]
Debt Instrument [Line Items]
Advances received				$ 25,000,000
Debt maturity date				Sep. 15, 2007
Fixed rates advances				3.64%
Federal Home Loan Bank [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Advances received		$ 25,000,000
Debt maturity date		Nov. 27, 2007
Fixed rates advances		2.70%
Libor Rate [Member] | Trust I [Member]
Debt Instrument [Line Items]
Adjust basis points on variable rate, percentage						2.75%
Libor Rate [Member] | Trust II [Member]
Debt Instrument [Line Items]
Adjust basis points on variable rate, percentage						2.31%
Libor Rate [Member] | Trust III [Member]
Debt Instrument [Line Items]
Adjust basis points on variable rate, percentage						2.29%
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			3-month LIBOR rate plus 198 basis points