Fair Value Measurements - Summary of Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Dec. 31, 2015
Assets
Securities available for sale	$ 479,609	$ 451,770
State tax credits held for sale	$ 4,801	5,941
Liabilities
State tax credit term	10 years
Years of tax credits generated	10 years
Portion at Other than Fair Value, Fair Value Disclosure
Assets
State tax credits held for sale	$ 39,400
Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	479,609	451,770
State tax credits held for sale	48,959	49,588
Derivative financial instruments	2,099	1,155
Liabilities
Derivative financial instruments	2,099	1,155
Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	99,058	99,008
Obligations of states and political subdivisions
Assets
Securities available for sale	38,336	41,701
Residential mortgage-backed securities
Assets
Securities available for sale	342,215	311,061
Recurring basis \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	479,609	451,770
State tax credits held for sale	4,801	5,941
Derivative financial instruments	2,099	1,155
Total assets	486,509	458,866
Liabilities
Derivative financial instruments		1,155
Total liabilities	2,099	1,155
Recurring basis \| Obligations of U.S. Government-sponsored enterprises \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	99,058	99,008
Recurring basis \| Obligations of states and political subdivisions \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	38,336	41,701
Recurring basis \| Residential mortgage-backed securities \| Estimate of Fair Value Measurement [Member]
Assets
Securities available for sale	342,215	311,061
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Securities available for sale	0	0
State tax credits held for sale	0	0
Derivative financial instruments	0	0
Total assets	0	0
Liabilities
Derivative financial instruments	0	0
Total liabilities	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Obligations of states and political subdivisions
Assets
Securities available for sale	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Residential mortgage-backed securities
Assets
Securities available for sale	0	0
Recurring basis \| Significant Other Observable Inputs (Level 2)
Assets
Securities available for sale	476,515	448,693
State tax credits held for sale	0	0
Derivative financial instruments	2,099	1,155
Total assets	478,614	449,848
Liabilities
Derivative financial instruments	2,099	1,155
Total liabilities	2,099	1,155
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	99,058	99,008
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Obligations of states and political subdivisions
Assets
Securities available for sale	35,242	38,624
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Residential mortgage-backed securities
Assets
Securities available for sale	342,215	311,061
Recurring basis \| Significant Unobservable Inputs (Level 3)
Assets
Securities available for sale	3,094	3,077
State tax credits held for sale	4,801	5,941
Derivative financial instruments	0	0
Total assets	7,895	9,018
Liabilities
Derivative financial instruments	0	0
Total liabilities	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Obligations of U.S. Government-sponsored enterprises
Assets
Securities available for sale	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Obligations of states and political subdivisions
Assets
Securities available for sale	3,094	3,077
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Residential mortgage-backed securities
Assets
Securities available for sale	$ 0	$ 0

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value of financial and nonfinancial obligations.

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