Fair Value Measurements (Details 2) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets:
Investment securities, available-for-sale	$ 850,467	$ 791,727
Mortgages held for sale	15,849	9,825
U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	420,833	389,669
U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	132,975	122,990
Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	252,574	236,297
Corporate debt securities
Assets:
Investment securities, available-for-sale	35,076	34,383
Foreign government and other securities
Assets:
Investment securities, available-for-sale	807	809
Total debt securities
Assets:
Investment securities, available-for-sale	842,265	784,148
Marketable equity securities
Assets:
Investment securities, available-for-sale	8,202	7,579
Total
Assets:
Investment securities, available-for-sale	850,467	791,727
Mortgages held for sale	15,849	9,825
Level 1
Assets:
Investment securities, available-for-sale	28,366	27,458
Mortgages held for sale	0	0
Level 2
Assets:
Investment securities, available-for-sale	818,595	758,932
Mortgages held for sale	15,849	9,825
Level 3
Assets:
Investment securities, available-for-sale	3,506	5,337
Mortgages held for sale	0	0
Recurring \| Total
Assets:
Investment securities, available-for-sale	850,467	791,727
Mortgages held for sale	15,849	9,825
Total	872,937	811,411
Liabilities:
Total	6,743	10,044
Recurring \| Total \| Interest rate swap contracts
Assets:
Accrued income and other assets	6,621	9,859
Liabilities:
Accrued expenses and other liabilities	6,743	10,044
Recurring \| Total \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	420,833	389,669
Recurring \| Total \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	132,975	122,990
Recurring \| Total \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	252,574	236,297
Recurring \| Total \| Corporate debt securities
Assets:
Investment securities, available-for-sale	35,076	34,383
Recurring \| Total \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	807	809
Recurring \| Total \| Total debt securities
Assets:
Investment securities, available-for-sale	842,265	784,148
Recurring \| Total \| Marketable equity securities
Assets:
Investment securities, available-for-sale	8,202	7,579
Recurring \| Level 1
Assets:
Investment securities, available-for-sale	28,366	27,458
Mortgages held for sale	0	0
Total	28,366	27,458
Liabilities:
Total	0	0
Recurring \| Level 1 \| Interest rate swap contracts
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring \| Level 1 \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	20,164	19,879
Recurring \| Level 1 \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 1 \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 1 \| Corporate debt securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 1 \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 1 \| Total debt securities
Assets:
Investment securities, available-for-sale	20,164	19,879
Recurring \| Level 1 \| Marketable equity securities
Assets:
Investment securities, available-for-sale	8,202	7,579
Recurring \| Level 2
Assets:
Investment securities, available-for-sale	818,595	758,932
Mortgages held for sale	15,849	9,825
Total	841,065	778,616
Liabilities:
Total	6,743	10,044
Recurring \| Level 2 \| Interest rate swap contracts
Assets:
Accrued income and other assets	6,621	9,859
Liabilities:
Accrued expenses and other liabilities	6,743	10,044
Recurring \| Level 2 \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	400,669	369,790
Recurring \| Level 2 \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	130,276	118,462
Recurring \| Level 2 \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	252,574	236,297
Recurring \| Level 2 \| Corporate debt securities
Assets:
Investment securities, available-for-sale	35,076	34,383
Recurring \| Level 2 \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 2 \| Total debt securities
Assets:
Investment securities, available-for-sale	818,595	758,932
Recurring \| Level 2 \| Marketable equity securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 3
Assets:
Investment securities, available-for-sale	3,506	5,337
Mortgages held for sale	0	0
Total	3,506	5,337
Liabilities:
Total	0	0
Recurring \| Level 3 \| Interest rate swap contracts
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring \| Level 3 \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 3 \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	2,699	4,528
Recurring \| Level 3 \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 3 \| Corporate debt securities
Assets:
Investment securities, available-for-sale	0	0
Recurring \| Level 3 \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	807	809
Recurring \| Level 3 \| Total debt securities
Assets:
Investment securities, available-for-sale	3,506	5,337
Recurring \| Level 3 \| Marketable equity securities
Assets:
Investment securities, available-for-sale	$ 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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-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
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