Fair Value Measurements (Details 2) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets:
Investment securities, available-for-sale	$ 828,615	$ 791,727
Mortgages held for sale	19,986	9,825
U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	407,995	389,669
U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	132,829	122,990
Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	244,170	236,297
Corporate debt securities
Assets:
Investment securities, available-for-sale	35,615	34,383
Foreign government and other securities
Assets:
Investment securities, available-for-sale	810	809
Total debt securities
Assets:
Investment securities, available-for-sale	821,419	784,148
Marketable equity securities
Assets:
Investment securities, available-for-sale	7,196	7,579
Total
Assets:
Investment securities, available-for-sale	828,615	791,727
Mortgages held for sale	19,986	9,825
Level 1
Assets:
Investment securities, available-for-sale	27,210	27,458
Mortgages held for sale	0	0
Level 2
Assets:
Investment securities, available-for-sale	796,612	758,932
Mortgages held for sale	19,986	9,825
Level 3
Assets:
Investment securities, available-for-sale	4,793	5,337
Mortgages held for sale	0	0
Recurring basis \| Total
Assets:
Investment securities, available-for-sale	828,615	791,727
Mortgages held for sale	19,986	9,825
Total	863,669	811,411
Liabilities:
Total	15,354	10,044
Recurring basis \| Total \| Interest rate swap contracts
Assets:
Accrued income and other assets	15,068	9,859
Liabilities:
Accrued expenses and other liabilities	15,354	10,044
Recurring basis \| Total \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	407,995	389,669
Recurring basis \| Total \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	132,829	122,990
Recurring basis \| Total \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	244,170	236,297
Recurring basis \| Total \| Corporate debt securities
Assets:
Investment securities, available-for-sale	35,615	34,383
Recurring basis \| Total \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	810	809
Recurring basis \| Total \| Total debt securities
Assets:
Investment securities, available-for-sale	821,419	784,148
Recurring basis \| Total \| Marketable equity securities
Assets:
Investment securities, available-for-sale	7,196	7,579
Recurring basis \| Level 1
Assets:
Investment securities, available-for-sale	27,210	27,458
Mortgages held for sale	0	0
Total	27,210	27,458
Liabilities:
Total	0	0
Recurring basis \| Level 1 \| Interest rate swap contracts
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring basis \| Level 1 \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	20,014	19,879
Recurring basis \| Level 1 \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 1 \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 1 \| Corporate debt securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 1 \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 1 \| Total debt securities
Assets:
Investment securities, available-for-sale	20,014	19,879
Recurring basis \| Level 1 \| Marketable equity securities
Assets:
Investment securities, available-for-sale	7,196	7,579
Recurring basis \| Level 2
Assets:
Investment securities, available-for-sale	796,612	758,932
Mortgages held for sale	19,986	9,825
Total	831,666	778,616
Liabilities:
Total	15,354	10,044
Recurring basis \| Level 2 \| Interest rate swap contracts
Assets:
Accrued income and other assets	15,068	9,859
Liabilities:
Accrued expenses and other liabilities	15,354	10,044
Recurring basis \| Level 2 \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	387,981	369,790
Recurring basis \| Level 2 \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	128,846	118,462
Recurring basis \| Level 2 \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	244,170	236,297
Recurring basis \| Level 2 \| Corporate debt securities
Assets:
Investment securities, available-for-sale	35,615	34,383
Recurring basis \| Level 2 \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 2 \| Total debt securities
Assets:
Investment securities, available-for-sale	796,612	758,932
Recurring basis \| Level 2 \| Marketable equity securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 3
Assets:
Investment securities, available-for-sale	4,793	5,337
Mortgages held for sale	0	0
Total	4,793	5,337
Liabilities:
Total	0	0
Recurring basis \| Level 3 \| Interest rate swap contracts
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring basis \| Level 3 \| U.S. Treasury and Federal agencies securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 3 \| U.S. States and political subdivisions securities
Assets:
Investment securities, available-for-sale	3,983	4,528
Recurring basis \| Level 3 \| Mortgage-backed securities - Federal agencies
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 3 \| Corporate debt securities
Assets:
Investment securities, available-for-sale	0	0
Recurring basis \| Level 3 \| Foreign government and other securities
Assets:
Investment securities, available-for-sale	810	809
Recurring basis \| Level 3 \| Total debt securities
Assets:
Investment securities, available-for-sale	4,793	5,337
Recurring basis \| 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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