Fair Value Measurements (Details 2) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair value measurements
Investment securities available-for-sale	$ 1,291,340	$ 1,197,467
Assets:
Mortgages held for sale	9,351	12,885
U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	678,405	619,482
U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	85,669	81,127
Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	489,490	453,789
Corporate debt securities
Fair value measurements
Investment securities available-for-sale	37,076	42,369
Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	700	700
Total
Fair value measurements
Investment securities available-for-sale	1,291,340	1,197,467
Assets:
Mortgages held for sale	9,351	12,885
Level 1
Fair value measurements
Investment securities available-for-sale	118,956	80,285
Assets:
Mortgages held for sale	0	0
Level 2
Fair value measurements
Investment securities available-for-sale	1,170,477	1,115,030
Assets:
Mortgages held for sale	9,351	12,885
Level 3
Fair value measurements
Investment securities available-for-sale	1,907	2,152
Assets:
Mortgages held for sale	0	0
Recurring basis \| Total
Fair value measurements
Investment securities available-for-sale	1,291,340	1,197,467
Assets:
Mortgages held for sale	9,351	12,885
Total	1,332,002	1,257,006
Liabilities:
Total	32,005	47,681
Recurring basis \| Total \| Interest rate swap contracts
Assets:
Accrued income and other assets	31,311	46,654
Liabilities:
Accrued expenses and other liabilities	32,005	47,681
Recurring basis \| Total \| U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	678,405	619,482
Recurring basis \| Total \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	85,669	81,127
Recurring basis \| Total \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	489,490	453,789
Recurring basis \| Total \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	37,076	42,369
Recurring basis \| Total \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	700	700
Recurring basis \| Level 1
Fair value measurements
Investment securities available-for-sale	118,956	80,285
Assets:
Mortgages held for sale	0	0
Total	118,956	80,285
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
Fair value measurements
Investment securities available-for-sale	118,956	80,285
Recurring basis \| Level 1 \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 1 \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 1 \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 1 \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 2
Fair value measurements
Investment securities available-for-sale	1,170,477	1,115,030
Assets:
Mortgages held for sale	9,351	12,885
Total	1,211,139	1,174,569
Liabilities:
Total	32,005	47,681
Recurring basis \| Level 2 \| Interest rate swap contracts
Assets:
Accrued income and other assets	31,311	46,654
Liabilities:
Accrued expenses and other liabilities	32,005	47,681
Recurring basis \| Level 2 \| U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	559,449	539,197
Recurring basis \| Level 2 \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	83,762	78,975
Recurring basis \| Level 2 \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	489,490	453,789
Recurring basis \| Level 2 \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	37,076	42,369
Recurring basis \| Level 2 \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	700	700
Recurring basis \| Level 3
Fair value measurements
Investment securities available-for-sale	1,907	2,152
Assets:
Mortgages held for sale	0	0
Total	1,907	2,152
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
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 3 \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	1,907	2,152
Recurring basis \| Level 3 \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 3 \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 3 \| Foreign government and other securities
Fair value measurements
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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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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