Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Securities available-for-sale, at fair value	$ 693,487	$ 660,963
U.S. Treasury securities
ASSETS
Securities available-for-sale, at fair value	24,811	14,941
Obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	232,179	263,303
Collateralized mortgage obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	129,777	128,835
Residential mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	37,358	40,125
Commercial mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	125,604	69,204
Obligations of states and political subdivisions
ASSETS
Securities available-for-sale, at fair value	132,509	134,886
Marketable equity securities
ASSETS
Securities available-for-sale, at fair value	11,249	9,669
Fair Value Measurements, Recurring
ASSETS
Securities available-for-sale, at fair value	693,487	660,963
Trading securities held in a Rabbi Trust	4,410	4,021
Total securities	697,897	664,984
Total Assets	705,093	676,540
LIABILITIES
Total Liabilities	6,985	11,281
Fair Value Measurements, Recurring \| U.S. Treasury securities
ASSETS
Securities available-for-sale, at fair value	24,811	14,941
Fair Value Measurements, Recurring \| Obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	232,179	263,303
Fair Value Measurements, Recurring \| Collateralized mortgage obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	129,777	128,835
Fair Value Measurements, Recurring \| Residential mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	37,358	40,125
Fair Value Measurements, Recurring \| Commercial mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	125,604	69,204
Fair Value Measurements, Recurring \| Obligations of states and political subdivisions
ASSETS
Securities available-for-sale, at fair value	132,509	134,886
Fair Value Measurements, Recurring \| Marketable equity securities
ASSETS
Securities available-for-sale, at fair value	11,249	9,669
Fair Value Measurements, Recurring \| Interest Rate Swap
ASSETS
Derivative financial assets	6,960	11,295
LIABILITIES
Derivative financial liabilities	6,958	11,276
Fair Value Measurements, Recurring \| Interest Rate Lock Commitments
ASSETS
Derivative financial assets	236	261
Fair Value Measurements, Recurring \| Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	27	5
Fair Value Measurements, Recurring \| Level 1
ASSETS
Securities available-for-sale, at fair value
Trading securities held in a Rabbi Trust	4,410	4,021
Total securities	4,410	4,021
Total Assets	4,410	4,021
Fair Value Measurements, Recurring \| Level 1 \| U.S. Treasury securities
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Collateralized mortgage obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Residential mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Commercial mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Obligations of states and political subdivisions
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Marketable equity securities
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 1 \| Interest Rate Swap
ASSETS
Derivative financial assets	0	0
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring \| Level 1 \| Interest Rate Lock Commitments
ASSETS
Derivative financial assets	0	0
Fair Value Measurements, Recurring \| Level 1 \| Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring \| Level 2
ASSETS
Securities available-for-sale, at fair value	693,487	660,963
Trading securities held in a Rabbi Trust	0	0
Total securities	693,487	660,963
Total Assets	700,683	672,519
LIABILITIES
Total Liabilities	6,985	11,281
Fair Value Measurements, Recurring \| Level 2 \| U.S. Treasury securities
ASSETS
Securities available-for-sale, at fair value	24,811	14,941
Fair Value Measurements, Recurring \| Level 2 \| Obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	232,179	263,303
Fair Value Measurements, Recurring \| Level 2 \| Collateralized mortgage obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	129,777	128,835
Fair Value Measurements, Recurring \| Level 2 \| Residential mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	37,358	40,125
Fair Value Measurements, Recurring \| Level 2 \| Commercial mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	125,604	69,204
Fair Value Measurements, Recurring \| Level 2 \| Obligations of states and political subdivisions
ASSETS
Securities available-for-sale, at fair value	132,509	134,886
Fair Value Measurements, Recurring \| Level 2 \| Marketable equity securities
ASSETS
Securities available-for-sale, at fair value	11,249	9,669
Fair Value Measurements, Recurring \| Level 2 \| Interest Rate Swap
ASSETS
Derivative financial assets	6,960	11,295
LIABILITIES
Derivative financial liabilities	6,958	11,276
Fair Value Measurements, Recurring \| Level 2 \| Interest Rate Lock Commitments
ASSETS
Derivative financial assets	236	261
Fair Value Measurements, Recurring \| Level 2 \| Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	27	5
Fair Value Measurements, Recurring \| Level 3
ASSETS
Trading securities held in a Rabbi Trust	0	0
Fair Value Measurements, Recurring \| Level 3 \| U.S. Treasury securities
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Collateralized mortgage obligations of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Residential mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Commercial mortgage-backed securities of U.S. government corporations and agencies
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Obligations of states and political subdivisions
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Marketable equity securities
ASSETS
Securities available-for-sale, at fair value	0	0
Fair Value Measurements, Recurring \| Level 3 \| Interest Rate Swap
ASSETS
Derivative financial assets	0	0
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring \| Level 3 \| Interest Rate Lock Commitments
ASSETS
Derivative financial assets	0	0
Fair Value Measurements, Recurring \| Level 3 \| Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	$ 0	$ 0

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, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Fair value of financial and nonfinancial obligations.

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